Question

the sum of the digits of a two-digit number is 7 if the digits are reversed the new number increased by 3 = 4 original number find the original number

Answer 1

Answer: 16

Step-by-step explanation:

Let the one's digit be b and ten's digit be a. Then the number is 10a+b

Given the sum of digits = 7

a+b=7 -----(1)

If the digit is reverses, the number will be 10b+a.

Then 10b+a+3=4(10a+b)

⇒10b + a + 3 = 40a + 4b

⇒39a - 6b = 3

⇒13a-2b=1 ------(2)

(1) x 2 ---->

2a + 2b = 14 ------(3)

(2) + (3) ---->

15a=15

a=1

a+b=7

So b = 6

So the original number is 16