Question

The digits of a 2 digit number differ by 3. Is the digits are interchanged, and the resulting number is added to the original number, we get 143. What can be the number?

Answer 1

58

Explanation:

Hello, let's note the two digits a and b. the first number 'ab' can be written as 10a +b. For instance if this is 24 it can be written 20 + 4.

If the digits are interchanged the number become 'ba' so 10b + a

We can say that 10a + b + 10b + a = 143

11(a+b)=143

We divide by 13 both sides and we take

a+b = 143/11 = 13

and we know that the digits differ by 3 so b = a + 3

then a + b = a + 3 + a = 2a + 3 = 13

so 2a = 10 and then a = 5

Finally, b = 5+3=8 so the number is 58.

And we can verify that 58 + 85 = 143.

Thanks

Answer 2

• Let the unit digit be x and tens digit be x + 3

• Therefore, the original number = 10(x + 3) + x

• On interchanging, the number formed = 10x + x + 3

❍ According to Question now,

➥ 10(x + 3) + x + 10x + x + 3 = 143

➥ 10x + 30 + 12x + 3 = 143

➥ 22x + 33 = 143

➥ 22x = 143 - 33

➥ 22x = 110

➥ x = 110/22

➥ x = 5

__________________...

Therefore,

The unit digit number = x = 5

The tens digit number = x + 3 = 5 + 3 = 8

__________________...

The original number = 10(x + 3) + x

The original number = 10(5 + 3) + 5

The original number = 50 + 30 + 5

The original number = 85

Hence,the original number is 85.