SAT Math Question of the Day

Math Category: Roots Level 2:

Q: √ 20

  1. 5 √ 2
  2. 5 √ 3
  3. 2 √ 5
  4. 3 √ 5
  5. 4 √ 5

UNANSWERED.

The correct answer is C.

A: The answer is 2 √ 5 .
√ 20 = √ (2)(2)(5)
There are two 2's under the root sign, so the 2 can be moved to outside the root, leaving 2 √ 5 .