GRE Math Problems

Most common pythagorean triples: a² + b² = c²

* 3-4-5 *5-12-13 *8-15-17 *7-24-25

A multiple choice test contains 4 questions, and each question has 5 answer choices. In how many ways can the test be completed if every question is answered?

5×5×5×5= 5⁴=625

A 3 person committee must be selected from seven people. If Rani and Sergio cannot be on the same committee, how many different committees are possible? A) 10 B) 15 C) 20 D) 25 E) 30

Note if RS_ there is only one spot left, therefore 7-2=5 and five options.

In how many ways can the five letters J, K, L, M and N be arrange such that the L is not in the middle?

Once you have placed the restriction in the third spot you now have equal restrictions and can start anywhere, 5-1= 4, then 3, 2, 1

A certain office has 6 employees, and there are 15 ways to choose R employees to be on the party planning committee. QA) R QB) 3

therefore, D is the correct answer

How many 3- digit integers greater than 499 have exactly two repeating digits? A) 90 B) 105 C) 108 D) 135 E) 140

three outcomes. 1) D,S,S 2)S,D,S 3)S,S,D therefore, 45×3=135