Question

In a two digit number. The sum of the digits is equal to i and product of the digits is equal to20. What is the number

Answer 1

Step-by-step explanation:

let x= once digit and y is tenth digit.

Then , number is 10y+x

So, if the digits interchange their places, then the number is 10x+y 

now, 

xy=20 ....(i) 

10y+x+9=10x+y

or 9x-9y=9

or x-y=1 ..(ii) 

From (i) and (ii) , we get 

x(x-1)=20=4X5

x=4 or 5 , but as x-y=1 , then x=5 and y=4 

The number is 45.