Question

Colin was thinking of a number. Colin doubles it, then adds 9 to get an answer of 95.4. What

was the original number?

Answer 1

43.2

Explanation:

Set up an equation to model the situation;

2x + 9 = 95.4

"x" represents the unknown number. 2x is present because the number is double. 9 is added because the problem says that Colin added 9. This is set equal to 95.4, because the result attained is 95.4.

Solve the equation using inverse operations;

2x + 9 = 95.4

-9 -9

2x = 86.4

/2 /2

x = 43.2