Math Word Problems Demystified - A Self Teaching Guide

EXAMPLE:A person has $5000 to invest and decides to invest part of it
at 4% and the rest of it at 6^12 %. If the total interest for the year from the
amounts is $245, how much does the person have invested at each rate?

SOLUTION:

GOAL: You are being asked to find the amounts of money invested at 4%
and 6^12 %.

STRATEGY: Let x¼the amount of money invested at 4% and
($5000
x)¼the amount of money invested at 6^12 %. Then set up a table as
shown.

Principal  Rate ¼ Interest

First investment x 4% 4%x

Second investment 5000 
x 612 %6^12 %(5000
x)

The equation is

Interest on the firstþInterest on second¼Total interest

investment investment

4 %xþ 6

1

2

%ð 5000 
xÞ¼$ 245

IMPLEMENTATION: Solve the equation:

4 %xþ 6

1

2

%ð 5000 
xÞ¼ 245

0 : 04 xþ 0 : 065 ð 5000 
xÞ¼ 245

0 : 04 xþ 325 
 0 : 065 x¼ 245

 0 : 025 xþ 325 ¼ 245

 0 : 025 xþ 325 
 325 ¼ 245 
 325

 0 : 025 x¼
 80

LESSON 15 Solving Finance Problems 161