Question

The tens digit of a certain number is five more than the units digit. The sum of the digits is 9. Find the number

Answer 1

Answer:

72

Step-by-step explanation:

Let the digits be x and y

X+y=9 - - (1(

X=y+5--(2)

Substituting 2 in 1

Y+5+y=9

2y+5=9

2y=4

Y=2

X=7

Number is 72

Answer 2

Given :

• The tens digit of a certain number is five more than the units digit.

• The sum of the digits is 9.

To find :

• The original number = ?

Solution :

Let the number be 10x + y, the ten's digit be x and unit digit be y.

According to the first condition,

→ Ten's digit = Unit's digit + 5

→ x = y + 5

→ x - y = 5 ----(1)

According to the second condition,

→ Ten's digit + Unit's digit = 9

→ x + y = 9 --------(2)

Solving (1) and (2) :-

→ x - y = 5

→ x + y = 9

_________

→ 2x = 14

_________

→ 2x = 14

→ x = 14/2

→ x = 7

→ The value of x = 7

Substitute the value of x in equation (1) :-

→ x - y = 5

→ 7 - y = 5

→ - y = 5 - 7

→ - y = - 2

→ y = 2

→ The value of y = 2

Therefore, the ten's digit = 7 and the unit's digit = 2

The original number = 10x + y

The original number = 10(7) + 2

The original number = 72

Therefore, the original number = 72