Math Word Problems Demystified - A Self Teaching Guide

Findx:

xþy¼ 5000

xþ 1800 ¼ 5000

xþ 1800 
 1800 ¼ 5000 
 1800

x¼$ 3200

Hence, he has $3200 invested at 4% and $1800 invested at 6^12 %.

EVALUATION: Check the second equation.

4 %xþ 6

1

2

%y¼ 245

0 : 04 ð 3200 Þþ 0 : 065 ð 1800 Þ¼ 245

128 þ 117 ¼ 245

245 ¼ 245

Try These

Use two equations with two unknowns.

1. One number is 4 times another number. If their sum is 40, find the
   numbers.


2. The sum of the digits of a two-digit number is 14. If the digits are
   reversed, the new number is 18 more than the original number. Find
   the number.


3. A person has 18 coins, some of which are nickels and the rest of which
   are dimes. If the total amount of the coins is $1.30, find the number of
   nickels and dimes.


4. Matt is 4 times older than Mike. In 10 years, he will be twice as old as
   Mike. Find their ages.

220 LESSON 18 Using Two Equations