Among three numbers, the first is twice the second and thrice the third. If…
2023
Among three numbers, the first is twice the second and thrice the third. If the average of three numbers is 506, then what is the difference between the first and the third number?
- A.
123
- B.
567
- C.
345
- D.
552
Attempted by 8 students.
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Correct answer: D
Step-by-Step Solution
To solve this, we express the three numbers in terms of a single variable based on the provided relationships.
Define the variables:
Let the first number be 6x (this allows it to be divisible by both 2 and 3).
Since the first number (6x) is twice the second, the second number is 6x / 2 = 3x.
Since the first number (6x) is thrice the third, the third number is 6x / 3 = 2x.
Use the average to find x:
The average of the three numbers is 506.
(6x + 3x + 2x) / 3 = 506
11x / 3 = 506
11x = 1518
x = 1518 / 11 = 138.
Calculate the numbers and their difference:
The first number is 6 * 138 = 828.
The third number is 2 * 138 = 276.
The difference between the first and third numbers is 828 - 276 = 552.