Numbers (C10)

Seven times a two digit number is equal to four times the number obtained by reversing the order of its digits. If the difference of the digits is 3, determine the number.

Answer

Let the ten’s and the unit's digit be y and x respectively.

So, the number is 10y + x.

The number when digits are reversed is 10x + y.

Now, 7(10y + x) = 4(10x + y)

2y = x … (i)

Also, x – y = 3 … (ii)

Solving (i) and (ii), we get

y = 3 and x = 6

Hence, the number is 36.