A two-digit number is 4 times the sum of its digits. If... – Algebra

Algebrahard · Past Paper

A two-digit number is 4 times the sum of its digits. If 18 is added to the number, the digits are reversed. Find the number.

A24

B12

C36

D48

✓ Correct Answer: A — 24

10x+y = 4(x+y) -> 6x=3y -> y=2x. (10x+y)+18=10y+x -> 9y-9x=18 -> y-x=2. Substitute y=2x: 2x-x=2 -> x=2, y=4. Number is 24.

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