Now You Try

<p>A company excavated <code class='latex inline'>150</code> t of black coal that contained <code class='latex inline'>1.9\%</code> water and left it on the ground. After being rained on, the coal contained <code class='latex inline'>10\%</code> water. By what percent did the mass of the coal increase?</p>

<p>Sea water contains <code class='latex inline'>5\%</code> salt. How many kilograms of distilled fresh water must be added of <code class='latex inline'>25</code> kg of sea water to decrease the concentration of salt to <code class='latex inline'>2\%</code>?</p>

<p>Evan spend a total of <code class='latex inline'>\$ 18</code> on gourmet jellybeans and chocolate-covered almonds. The jellybeans cost <code class='latex inline'>\$ 12</code>/kg. The almonds cost <code class='latex inline'>\$ 21</code>/kg.</p><p>a) Write an equation to represent Evan's purchases.</p><p>b) Isolate the variable for the quantity of jellybeans in your equation.</p><p>c) If Evan bought 250g of almonds, how many grams of jellybeans did he buy?</p><p>d) If Evan bought 100 g of almonds, how many grams of jellybeans did he buy?</p>

<p>Happy Burger is made by combining cuts of pork and fat trim. The amount of fat in Happy Burger is limited by government regulations to no more than <code class='latex inline'>25\%</code>. A butcher has a supply of pork with fat content 20\%. He also has a supply of fat trim with fat content <code class='latex inline'>100\%</code>. He wants to make 20 kg of Happy Burger with a fat content of <code class='latex inline'>24\%</code>. How much pork and how much fat should he use?</p>

<p>Each gram of a mandarin orange has 0.26 mg of vitamin C and 0.13 mg of vitamin A. Each gram of a tomato has 0.13 mg of vitamin C and 0.42 mg of vitamin A. How many grams of mandarin oranges and tomatoes have 13 mg of vitamin C and 20.7 mg of vitamin A? </p>

<p>Each gram of a mandarin orange has 0.26 mg of vitamin C and 0.13 mg of vitamin A. Each gram of tomato has 0.13 mg of vitamin C and 0.42 mg of vitamin A. How many grams of mandarin oranges and tomatoes have 13 mg of vitamin C and 20.7 mg of vitamin A? </p>

<p>One type of fertilizer has 30% nitrogen and a second type has 15% nitrogen. If a farmer needs 600 kg Of fertilizer that is 20% nitrogen, how much of each type should the farmer mix together?</p>

<p>Ron needs 500 g of chocolate that is 86% cocoa for a truffle recipe.
fl He has one kind of chocolate that is 99% cocoa and another kind that
is 70% cocoa. How much of each kind of chocolate does he need to make the 86% cocoa blend? Round your answer to the nearest gram.</p>

<p> Mike has a bottle containing acid that is <code class='latex inline'>40\%</code> of 250 ml. To remove stains, the acid concentration needs to be <code class='latex inline'>60\%</code>. How much should Mike pour out his acid and replace with <code class='latex inline'>90\%</code> acid to get <code class='latex inline'>60\%</code> acid bottle?</p>

<p>A woodworking shop makes tables and chairs. To make a chair, 8 min is needed on the lathe and 8 min is needed on the sander. To make a table, 8 min is needed on the lathe and 20 min is needed on the sander. The lathe operator works 6 h/day, and the sander operator works 7 h/day. How many chairs and tables can they make in one day working at this capacity?</p>

<p>A chemist has one 30-L bottle of <code class='latex inline'>15\%</code> hydrochloric acid and one <code class='latex inline'>30-L</code>: bottle of <code class='latex inline'>90\%</code> hydrochloric acid. She mixes <code class='latex inline'>20 L</code> of <code class='latex inline'>60\%</code> hydrochloric acids and then puts <code class='latex inline'>5 L</code> of that solution back into the bottle containing the <code class='latex inline'>90\%</code> hydrochloric acid. How strong is the acid in that bottle now?</p><p><a href="https://youtu.be/A0iwZxy8DE4">Lecture video</a></p>

<p>Wayne wants to use a few pieces of silver to make a bracelet. Some of the jewellery is <code class='latex inline'>80\%</code> silver, and the rest is <code class='latex inline'>66\%</code> silver. Wayne needs <code class='latex inline'>30.00g</code> of <code class='latex inline'>70\%</code> silver for the bracelet. How much of each alloy should he use?</p><p><a href="https://www.youtube.com/watch?v=SMfnqFG8xQ0&feature=emb_logo">HINT 1</a>
<a href="https://youtu.be/8CuPYmE9R3A">HINT 2</a></p>

<p>A vinegar-water solution is used to wash windows. If 1200 L of a <code class='latex inline'>28\%</code> solution are required, how much of <code class='latex inline'>16\%</code> and <code class='latex inline'>36\%</code> solutions should be used?</p>

<p>A student read a book in three days. During the first day the student read <code class='latex inline'>25\%</code> of the book. During the second day, the student read <code class='latex inline'>65\%</code> of the rest, and during the third day the students read 42 pages. How many pages were there in the book?</p>

<p>One lawn fertilizer is <code class='latex inline'>24\%</code> nitrogen, and another is <code class='latex inline'>12\%</code> nitrogen. How much of each fertilizer should be mixed to obtain 100 kg of fertilizer that is <code class='latex inline'>21 \%</code> nitrogen?</p>

<p>A health-food company packs almond butter in jars. Some jars hold 250 g. Other jars hold 500 g. On Tuesday, the company packed 186.5 kg of almond butter in 511 jars. How many jars of each size did they pack?</p>

<p><code class='latex inline'>3</code> kg of alloy that contained <code class='latex inline'>65\%</code> silver were melted together with <code class='latex inline'>2</code> kg of alloy that contained <code class='latex inline'>72\%</code> silver. Find the percentage of silver in the obtained alloy.</p>

<p>Brand A fertilizer is <code class='latex inline'>32\%</code> phosphorus, while Brand B is <code class='latex inline'>18\%</code> phosphorus. How much of each must be used to produce 56 t of a <code class='latex inline'>24\%</code> mixture?</p>

<p>Lily needs 200 g of chocolate that is <code class='latex inline'>86\%</code> cocoa for a cake recipe. He has one kind of chocolate that is <code class='latex inline'>99\%</code> cocoa and another kind that is <code class='latex inline'>70\%</code> cocoa. How much of each kind of chocolate does he need to make the cake? Round your answer to the nearest gram.</p>

<p>Jim researched these nutrition facts:</p>
<ul>
<li><code class='latex inline'>1g</code> of soy milk has <code class='latex inline'>0.005g</code> of carbo hydrates and <code class='latex inline'>0.030g</code> of protein.</li>
<li><code class='latex inline'>1g</code> of vegetables has <code class='latex inline'>0.14 g</code> of carbohydrates and <code class='latex inline'>0.030 g</code> of protein.</li>
</ul>
<p>Jim wants his lunch to have <code class='latex inline'>50.000</code> g of carbohydrates and <code class='latex inline'>20.000</code> g of protein. How many grams of soy milk and vegetables does he need?</p>

<p>A chemist mixes hydrochloric acid solution of <code class='latex inline'>50\%</code> strength and <code class='latex inline'>40\%</code> strength to get 500 L of hydrochloric acid solution of <code class='latex inline'>46\%</code> strength. How many litres of the <code class='latex inline'>50\%</code> solution are used?</p>

<p>Roaneeds 500 g of chocolate that is 86% cocoa for a truffle recipe.
He has one kind of chocolate that is 99% cocoa and another kind that is 70% cocoa. </p><p>How much of each kind of chocolate does he need to make the 86% cocoa blend? Round your answer to the nearest gram.</p>

<p>A <code class='latex inline'>60\%</code> sulfuric acid solution will be mixed with a <code class='latex inline'>95\%</code> sulfuric acid solution to produce 2700 mL of a <code class='latex inline'>70\%</code> solution. How much of each is required?</p>

<p>One type of granola has 30% nuts, by mass. A second type of granola has 15% nuts. What mass of each type needs to be mixed to make 600 g of granola that will have 21% nuts?</p>

<p>A metal alloy is <code class='latex inline'>25\%</code> copper. Another metal alloy is <code class='latex inline'>50\%</code> copper. How much of each should be used to make 500 g of an alloy that is <code class='latex inline'>45\%</code> copper?</p>

<p>Each gram of a mandarin orange has 0.26 mg of vitamin C and 0.13 mg of vitamin A. Each gram of a tomato has 0.13 mg of vitamin C and 0.42 mg of vitamin A. How many grams of mandarin oranges and tomatoes have 13 mg of vitamin C and 20.7 mg of vitamin A? </p>

<p>Chemex Lab needs to make 500 L of a 34% acid solution for a customer. The lab has 25% and 50% acid solutions available to make the order. How many litres of each should be mixed to make the 34% solution?</p>

<p>Sam is a jewellery artist. She needs to mix metals to make her products. Pure gold is 24-karat and is very soft. It is usually mixed with other metals such a silver to make it harder. Same has some 18-karat gold (18/24 pure gold) and some 9-kara gold (9/24 pure gold). what mass of each type of gold should she use to make 600 g of 15-karat gold?</p>

<p>For his coffee shop, Abdul wants to make a mocha-java blend that will sell for <code class='latex inline'>\$18</code>/kg. The mocha coffee beans sell
for <code class='latex inline'>\$20</code>/kg, and the java coffee beans sell for <code class='latex inline'>\$15</code>/kg. How many kilograms of each kind of coffee bean should he use to make <code class='latex inline'>50</code> kg of the mocha-java blend? </p>

<p>Chemex Lab needs to make 500 L of a 34% acid solution for a customer. The lab has 25% and 50% acid solutions available to make the order. How many litres of each should be mixed to make the 34% solution?</p>

<p>Amy needs to make 10L of <code class='latex inline'>42\%</code> sulphuric acid solution. In the supply room, she finds bottles <code class='latex inline'>30\%</code> sulphuric acid solution and <code class='latex inline'>60\%</code> sulphuric acid solution. What volume of each solution should she mix in order to make the <code class='latex inline'>42\%</code> solution?</p>

<p>A lab technician needs to make 400 kg of <code class='latex inline'>51\%</code> alcohol solution by combining <code class='latex inline'>60\%</code> alcohol solution by mass and <code class='latex inline'>40\%</code> alcohol solution by mass. How many kilograms of the <code class='latex inline'>40\%</code> solution must be used?</p>

<p>Milk and cream contain different percents of butterfat. How much <code class='latex inline'>3\%</code> milk needs to be mixed with how much <code class='latex inline'>15\%</code> cream to give <code class='latex inline'>20 L</code> of <code class='latex inline'>6\%</code> cream?</p>