Question

help me with these questions as its tooo hard

Answer 1

Let the digit in the tens place be x and the digit in the ones place be y.

⇒ The number is (10x + y)

Given that the sum of the digit is 3:

⇒ x + y = 3

⇒ x = 3 - y ---------------- [ 1 ]

Given that if 9 is subtracted from the number, the digit is interchanged:

⇒ (10x + y) - 9 = 10y + x

⇒ 10x + y - 9 = 10y + x

⇒ 9x = 9 + 9y

⇒ x = 1 + y ---------------- [ 2 ]

Solve x and y:

Equate equation [ 1 } and [ 2 ]:

3 - y = 1 + y

2y = 2

y = 1 ------------ Sub into [ 1 ] to find x

x = 3 - y

x = 3 - 1

x = 2

Find the number:

The number = 10x + y = 10(2) + 1 = 21

Answer: The number is 21