Question

Alondra challenges you to play a math game. She says, "I am thinking of a whole number. If you double my number and subtract 6, the result is less than 2 units away from 0. What number am I thinking of?"

Answer 1

3

Explanation:

Let "a" represent Alondra's number. Then the math she performs on it is ...

2a-6 . . . .double my number and subtract 6

| 2a-6 | < 2 . . . . . the result is less than 2 units from zero

This absolute value expression can be "unfolded" to two of them ...

-2 < 2a -6 < 2

Dividing by 2 gives ...

-1 < a -3 < 1

Adding 3, we get ...

2 < a < 4

The only whole number in this range is ...

a = 3

Alondra is thinking of the number 3.