Answer: 10.4
Step-by-step explanation:
Let the number that Colin is thinking of be represented as x.
We are informed that Colin halves the number and gets an answer of 5.2. This can be written as:
x ÷ 1/2 = 5.2
0.5x = 5.2
Divide through by 0.5
0.5x/0.5 = 5.2/0.5
x = 10.4
The number is 10.4
