Question

A two-digit number is 9 more than
four times of the number obtained by
interchanging its digits. If the product
of digits in the two-digit number is 8,
then what is the number?​

Answer 1

Step-by-step explanation:

Given:-

Products of x & y is 8. The only 2 possible options are (2,4) & (1,8).

The number is 9 more than 4 times of number obtained by interchanging the digits. That means the tens digit is geater than units. Therefore the first digit can be either of 4 or 8. Hence the numbers can be 42 or 81.

Lets compare the numbers with given conditions:-

Option-1: If the digits are be 4,2. The 42 is actually less than 4 times of 24(i.e. 96).

Option-2: If the digits are 8,1. The number 81 is greater than 4 times of 18( i.e. 72). And the number is also 9 more than 72.

Hence the number is 81.