Question

Question:

The sum of the digits in a 2-digit number is 7. If 9 is subtracted from the number, its digits are reversed. Find the number.


♧Answer needed with full explanation​

Answer 1

Answer:

43 (original number) and 34 (reversed number)

Step-by-step explanation:

Given that the sum of the digits in a 2-digit number is 7. When 9 is subtracted from the number, its digits are reversed.

We need to find out the number.

Assumption: Let's say that tens digit number is x and ones digit number is y.

Therefore,

Original number = 10x + y and reserved number = 10y + x

As per given statement equations are :

• x + y = 7
• 10x + y - 9 = 10y + x

Now,

→ x + y = 7

→ x = 7 - y --------- (eq 1)

→ 10x + y - 9 = 10y + x

→ 10x - x + y - 10y = 9

→ 9x - 9y = 9

→ x - y = 1 ---------- (eq 2)

Substitute value of x from (eq 1) in (eq 2)

→ 7 - y - y = 1

→ -2y = -6

→ y = 3

Substitute value of y in (eq 1)

→ x = 7 - 3

→ x = 4

Hence, the original number is 43 and reversed number is 34.