Multiple choice

The mean of three numbers is 55. One of the numbers, a is 50% more than the sum of the other two numbers. What is the value of a?

  1. 77

  2. 99

  3. 121

  4. 143
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mean of 3 numbers = 55, so sum = 165. Let the numbers be a, x, y. a + x + y = 165. Given a = 1.5(x + y). Substitute (x+y) = a/1.5: a + a/1.5 = 165. a + 2a/3 = 165. 5a/3 = 165. a = 165 * 3 / 5 = 33 * 3 = 99.

AI explanation

The sum of the three numbers is 55 times 3, which equals 165, so the sum of the other two numbers is 165 minus a. Since a is 50% more than the sum of the other two numbers, the equation is a = 1.5 times (165 minus a), which simplifies to 2.5a = 247.5. Solving for a gives a value of 99.

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