A. 24
B. 26
C. 27
D. 45
Let the ten’s digit be X. The one digit is Y.
Given that a two digit number is 3 times the sum of its digits.
10x+y = 3(x + y)
10x + y = 3x + 3y
7x = 2y ——————- (1)
Given that if 45 is added to it, the digits are reversed.
10x + y = 10y – x – 45
9x = 9y – 45
x = y – 5 ——————- (2)
Substitute (2) in (1), we get
7(y-5) = 2y
7y – 35 = 2y
y = 7.
Substitute y = 7 in (2), we get
x = 7 – 5 =2.
The values of x and y are 72.
The number is 27