ISEE Mathematics Achievement Question 316: Answer and Explanation

Home > ISEE Test > ISEE Mathematics Achievement Practice Tests

Test Information

Question: 316

16. What is the greatest common factor of (3xy)3 and 3x2y5 ?

  • A. xy
  • B. 3x2y5
  • C. 3x2y3
  • D. 27x3y3

Correct Answer: C

Explanation:

C First, simplify the first expression: (3xy)3 = 33x3y3 = 27x3y3. While comparing it to the other expression, 3x2y5, you can work in bite-sized pieces. Start with the coefficients: the greatest common factor of 3 and 27 is 3. Eliminate (A) and (D) since those don't contain 3. Both of the remaining answers contain x2, so compare y in the two expressions. One has y3 = y × y × y and the other has y5 = y × y × y × y × y. The greatest common factor is y3 since both expressions have at least 3 y's. Eliminate (B). The correct answer is (C).

Previous       Next