Math Word Problems Demystified - A Self Teaching Guide

Solve foryin the first equation.

y¼ 14 
x

Substitute in the second equation and solve forx.

10 xþð 14 
xÞþ 18 ¼ 10 ð 14 
xÞþx

10 xþ 14 
xþ 18 ¼ 140 
 10 xþx

9 xþ 32 ¼ 140 
 9 x

9 xþ 9 xþ 32 ¼ 140 
 9 xþ 9 x

18 xþ 32 ¼ 140

18 xþ 32 
 32 ¼ 140 
 32

18 x¼ 108

181 x

18

¼

108

18

x¼ 6

Solve fory:

xþy¼ 14

6 þy¼ 14

6 
 6 þy¼ 14 
 6

y¼ 8

3. Letx¼the number of nickels
   andy¼the number of dimes

xþy¼ 18

5 xþ 10 y¼ 130

222 LESSON 18 Using Two Equations