Question

in a two digit number the digit at units place is equal to the square of the digit at tens place if 18 is addef to the number the digit get interchanged find the number

Answer 1

let the ten's place digit = x
unit place digit = x²
the number = 10x+x²---(1)
if 18 is add to the number the digits get interchenged
10x+x ²+18 =10x²+x
0=10x²+x-10x-x²-18
0=9x²-9x-18
divide each term with 9
0=x²-x-2
x²-x-2=0
x²-2x+x-2=0
x(x-2)+1(x-2)=0
⇒(x-2)(x+1)=0
therefore
x-2 =0 or x+1 =0
x=2 or x=-1
x should not be negative
x=2
the number = 10x+x²
=10*2+2²
=20+4
=24

Answer 2

there are  three possibility -
11 ->  11+18=29
24 -> 24+18=42
39 -> 39+18=57
so 24 is correct ans