Question

There are 4 different digits 1, 2, x, y. From those 4 digits, you can make 18 natural numbers with 3 different digits, and the sum of those 18 numbers is 4508. Calculate x+y.

A) 15
B) 18
C) 21
D) 24

Answer 1

The values of x and y in the equation result in x+y = 15

Step-by-step explanation:

The sum of the 18 natural numbers formed using the 4 different digits 1, 2, x, and y is 4508. We need to find the values of x and y. Let's first find the sum of the digits 1 and 2, which is 1+2 = 3. The sum of the remaining 16 numbers is 4508 - (1+2) = 4505. Since the sum of any three different digits is always divisible by 3, we can conclude that x+y must be a multiple of 3. Now we need to find two numbers whose sum is a multiple of 3 and their sum is 4505. By trial and error, we find that when x = 7 and y = 8, their sum is 7+8 = 15, which is a multiple of 3. Therefore, the values of x and y are 7 and 8 respectively. So, x+y = 7+8 = 15.