Math Word Problems Demystified - A Self Teaching Guide

0 : 051 x

0 : 051

¼

0 : 6

0 : 05

x¼12 ounces of Mixture 1

20 
x¼ 20 
 12 ¼8 ounces of Mixture 2

Hence 12 ounces of the 10% solution should be mixed with 8 ounces of the
5% solution to get 20 ounces of an 8% solution.

EVALUATION: Check the equation:

10 %xþ 5 %ð 20 
xÞ¼ 8 %ð 20 Þ

10 %ð 12 Þþ 5 %ð 8 Þ¼ 8 %ð 20 Þ

1 : 2 þ 0 : 4 ¼ 1 : 6

1 : 6 ¼ 1 : 6

EXAMPLE:A craftsperson has two alloys of silver. The first one is 70%
pure silver and the second one is 50% silver. How many ounces of each must
be mixed to have 12 ounces of an alloy which is 65% silver?

SOLUTION:

GOAL: You are being asked to find how much of each alloy should be mixed
to get 12 ounces of an alloy which is 65% silver.

STRATEGY: Letx¼the amount of the 70% silver alloy and 12
x¼the
amount of the 50% silver alloy; then

Amount  Percent ¼ Amount of pure

Alloy 1 x 70% 70%x

Alloy 2 12 
x 50% 50%(12
x)

Alloy 3 12 65% 65%(12)

LESSON 14 Solving Mixture Problems 149