Question

The sum of digit of two digit no is 10.if 18 be subtracted from it the digit in resulting no will be equal .The no is

Answer 1

Let x = 10's digit , y = units digit and z = the resulting equal digits

Writing an equation for each statement,

GIVEN ,
x + y = 10
or
y = (10-x)..... 1

GIVEN ,
10x + y - 18 = 10z + z
10x + y = 11z + 18...... 2

From 1 and 2

10x + (10-x) = 11z + 18
10x - x = 11z + 18 - 10
9x = 11z + 8

The values for x and z are x=7 and z=5 in this equation (by solving ).

x = 7, y = 3, z = 5

The number is 73..... ANSWER