Question

The sum of the digits of a two digit number is 7. If we add 45 to the number, the digits are interchanged. Find the number

Answer 1

let the ones place digital=x
and tens place digit= y
no. formed= 10x+y
no. formed after inter changing= 10y+x
ATQ
10x+y+45=10y+x
9y-9x=45
y-x=5


now add eq x+y=7 and y-x=5
y=6
and x=1

now the no.will be 16