The average of five numbers is 12. Four of them are 10, 11, 14 and 15. What is the fifth number?
Answer and explanation
Correct answer: D. 10
- Step 1: The sum of all five is 5 x 12 = 60. Step 2. The four known numbers add up to 50. Step 3. The fifth is 60 - 50 = 10. Answer: 10. Why not the others: these values give a different sum.
Practise more Arithmetic, Algebra, Geometry and Counting (Set 3).
Free questions with an explanation for every one, and full timed GRE mock tests.
More Arithmetic, Algebra, Geometry and Counting (Set 3) questions
- If 3x + 7 = 25, what is the value of x?
- What is 15 percent of 240?
- Two numbers are in the ratio 3 to 5 and their sum is 64. What is the larger number?
- A bag has 4 red marbles and 6 blue marbles. Two marbles are drawn without replacement. What is the probability that both are red?
- A right triangle has legs of length 6 and 8. What is its perimeter?
- A circle has a circumference of 10 pi. What is its area?