SAT Math Question of the Day

Math Category: Algebraic Equations With One Unknown Variable:

Q: a/2 - a/3 = 1. What's a?

  1. 1/2
  2. 2
  3. 3
  4. 6
  5. 12

UNANSWERED.

The correct answer is D.

A: The answer is 6.

The Algebra Way:
Times by the Least Common Denominator. It's 6, because 2 * 3 = 6.
6 * a / 2 - 6 * a / 3 = 6
3a - 2a = 6
a = 6

Or use the Substitution Way:
Try answer C) first.
Plug 3 into a/2 - a/3 = 1 3/2 - 3/3 = 1 3/2 - 1 = 1 1/2 = 1 No way.

Try D) next. Plug in 6. a/2 - a/3 = 1 6/2 - 6/3 = 1 3 - 2 = 1 1 = 1 Yay!