Question

in a two digit no the units digit is four times the tens digit and the sum of digits is 10 find no

Answer 1

This is the long version

If x is the digit in the unit place and y is the digit in the ten’s place,

Then x = 4y and x+ y = 10 (given)

Substitute for x in the equation x + y = 10

4y + y = 10

5y = 10

y = 2

But x = 4y

Therefore x = 8

The number is 28

Let’s verify our answer:

The digit in the unit place (8) is four times the digit in the ten’s place (2) - yes

The sum of the digits is 10 - yes, 2 + 8 = 10

This is the short version

Trial and error

If the digit in the unit place is 1, then the digit in the ten’s place is 4 (no good because total has to be 8)

Let's try 2 as the digit in the unit place, then the digit in the ten's place is 8 (good because total has to be 10)

So number is 28