The difference between two numbers is 18. If four times the second number is less than three times the first number by 18, then what is the sum of these two numbers?

A) 100

B) 80

C) 86

D) 90

Correct answer:
D) 90

Description for Correct answer:
Let first number = x

and second number = y

According to the question.

x - y = 18 ...(i)

and 3x - 4y = 18 ...(ii)

On multiplying Eq. (i) by 3 and then subtracting Eq. (ii) from it, we get

3x - 3y = 54

3x - 4y = 18

y = 36

On putting the value of y in Eq. (i), we get

x = 18 + y = 18 + 36 => x = 54

Therefore, Required sum = x + y = 54+ 36 = 90


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