Question

The sum of the digits of a 2-digit number is 10. The digit in one's place is nine times the digit at ten's place. Find the number.​

Answer 1

Step-by-step explanation:

Let unit and ten’s digit be x&y

X+Y=10

y=10-X

X=9(10-x)

X=90-9x

A/Q

90-9x+(10-x)=10

90-9x+10-x=10

100-10x=10

-10x=-90

x=9

Hence,

unit’s digit=9=x

Ten’digit=x+y=10

9+y=10

y=1

so, the number is 91