Example Find two numbers whose sum is 24 and whose difference is 4

You are looking for two numbers of which assume the smaller one to be 'x'

As the difference is 4

The greater number is x + 4

Setting up the equation as

x + (x + 4) = 24

2 x + 4 = 24

2 x = 20

x = 10

Therefore, the two numbers are 10 and 14.

Check:

Sum = 10 + 14

       = 24 and

difference
      = 14 - 10

      = 4

If we assume the age of Tom to be x years, then his age a few years before, his age after a few years, the ages of his brothers and sisters relative to him etc. can be seen in the information given below :

[next page]

Index

9.1 - Definition and Solving Techniques
9.2 - Use of Simultaneous Linear Equations

Chapter 1