Math Word Problems Demystified - A Self Teaching Guide

EVALUATION: The sum of 4þ 8 ¼12. The sum of the reciprocals is

1

4 þ

1

8 ¼

2

8 þ

1

8 ¼

3

8 :

Try These

1. The square of a number plus 5 is equal to 86. Find the number.


2. One number is 6 more than another number, and the product of the
   two numbers is 91. Find the numbers.


3. If the product of two consecutive odd numbers is 255, find the
   numbers.


4. One number is 3 more than another number. If the square of the
   smaller number is 19 more than three times the larger number, find
   the numbers.


5. A larger pipe can fill a tank in 32 minutes less time than a smaller pipe.
   If they both are turned on at the same time, they can fill the tank in 30
   minutes. How long does it take each pipe alone to fill the tank?

SOLUTIONS:

1. Letx¼the number

x^2 þ 5 ¼ 86

x^2 þ 5 
 86 ¼ 86 
 86

x^2 
 81 ¼ 0

ðx
 9 Þðxþ 9 Þ¼ 0

xþ 9 ¼ 0 x
 9 ¼ 0

xþ 9 
 9 ¼ 0 
 9 x
 9 þ 9 ¼ 0

x¼
 9 x¼ 9

The answer is 9 and
9.

236 LESSON 19 Using Quadratic Equations