Math Word Problems Demystified - A Self Teaching Guide

STRATEGY: Letx¼the amount invested at 2%, 3x¼the amount of money
invested at 5%, andxþ 600 ¼the amount of money invested at 3%.

Principal  Rate ¼ Interest

First investment x 2% 2%x

Second investment 3 x 5% 5%(3x)

Third investment xþ 600 3% 3%(xþ600)

The equation is 2%xþ5%(3x)þ3%(xþ600)¼$98

IMPLEMENTATION: Solve the equation:

2 %xþ 5 %ð 3 xÞþ 3 %ðxþ 600 Þ¼$ 98

0 : 02 xþ 0 : 05 ð 3 xÞþ 0 : 03 ðxþ 600 Þ¼ 98

0 : 02 xþ 0 : 15 xþ 0 : 03 xþ 18 ¼ 98

0 : 20 xþ 18 ¼ 98

0 : 20 xþ 18 
 18 ¼ 98 
 18

0 : 20 x¼ 80

0 : 201 x

0 : 201

¼

80

0 : 2

x¼ 400

3 x¼ 3 ð 400 Þ¼ 1200

xþ 600 ¼ 400 þ 600 ¼ 1000

Hence the investor invested $400 at 2%, $1200 at 5%, and $1000 at 3%.

LESSON 15 Solving Finance Problems 165