There are two numbers such that the first number is twice the second number. If their average is 30, then what is the positive difference between the two numbers?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 20.
Average = Sum of the numbers/total numbers
Let the second number be x.
According to the given question, first number = 2x.
Average = (x + 2x)/2
⇒ 30 = 3x/2
⇒ 60 = 3x
⇒ x = 20
Now the first number = 2 × 20 = 40
and the second number = x = 20
Difference = 40 - 20 = 20.
Hence the required difference is 20.