Question

The sum of the digit in a two-digit number is 10. if 18 is subtracted from the number, the result is the number with the digit reversed. find the number.

Answer 1

Heya !!✌✌✌

Let u = unit's digit and t = ten's digit.

Then 10t+u = the number

The following equation are formed :

t+u = 10 (sum is 10.)

10t+u-18 = 10u+t (number -18 = number with digits reversed)

9t-9u = 18

t-u = 2

Adding (1)&(2), we get

2t = 12 therefore t = 12/2 = 6

substituting in(1), 6+u = 10 therefore, u = 10-6 = 4

Therefore, the number is 10t+u = 10×6+64.

It helps you....✌✌✌

Answer 2

Let x = 10's digit of a two digit number
Let y = units digit
Let z = the resulting equal digits
:
Write an equation for each statement:
:
"the sum of a two digit number is 10."
x + y = 10
or
y = (10-x)
:
" if 18 be subtracted from it, the digits in the resulting number will be equal."
10x + y - 18 = 10z + z
10x + y = 11z + 18
:
Substitute (10-x) for y
10x + (10-x) = 11z + 18
10x - x = 11z + 18 - 10
9x = 11z + 8
:
The single digit integer values for x and z are limited to x=7 and z=5 in this equation:
x = 7, y = 3, z = 5
:
The number is 73