Question

a number of 2 digit the digit the tenth place is 3 times the digit in the unit place .if 54 is subtracted from the number the number the digit get inverted find the number

Answer 1

let the unit digit be x
so
ten's digit=3x
{(10×3x)+x}-54={(10×x)+3x}
31x-54=13x
54=13x-31x
54=-18x
54+18=x
72=x