The correct option is C 48
Let the digit at units and tens place in the given number be x and y respectively.
Then, number = 10y + x ...(i)
Number formed by interchanging the digits = 10x + y
According to the given condition, we have
(10y + x) + (10x + y) = 132
and (10y + x) + 12 = 5(x + y)
⇒ 11x + 11y = 132 and 4x - 5y = 12
⇒ x + y - 12 = 0 ...(ii) and
4x - 5y - 12 = 0 ...(iii)
Solving these two equations:
Multiplying eq. (i) × 4, we get
4x + 4y = 48 ...(iv)
On subtracting (iii) from (iv), we get
9y = 36
⇒ y = 4
On substituting y = 4 in eq. (ii), we get
x + 4 - 12 = 0
⇒ x = 8
⇒ x = 8 and y = 4
On substituting the values of x and y in equation (1), we have
10y + x = 10 × 4 + 8 = 48
∴ The number is 48.