Question

17. A number consists of two digits. The digit at the tens place is twice that of the digit at units place. 18 is subtracted from the number, the digits are reversed. Find the number ?? pls answer fast​

Answer 1

Given :

• A number consists of two digits. The digit at the tens place is twice that of the digit at units place. 18 is subtracted from the number, the digits are reversed.

To find :

• Required number

Solution :

✦Let the ones digit x and tens digit be y

• Original number = (10y + x)

According to the given condition

✪ The digit at the tens place is twice that of the digit at units place

• y = 2x -----(i)

✪ 18 is subtracted from the number, the digits are reversed.

• Reversed number = (10x + y)

➡ (10y + x) - 18 = (10x + y)

➡ (10y + x) - (10x + y) = 18

➡ 10y + x - 10x - y = 18

➡ 9y - 9x = 18

➡ 9(y - x) = 18

➡ y - x = 2 -------(ii)

✪ Substitute the value of y in eqⁿ (ii) ✪

• y = 2x

➡ y - x = 2

➡ 2x - x = 2

➡ x = 2

✪ Now, put the value of x in eqⁿ (i) ✪

➡ y = 2x

➡ y = 2*2

➡ y = 4

Hence,

• Original number = (10y + x) = 42
• Reserved number = (10x + y) = 24

Answer 2

Step-by-step explanation:

Assume that the ten's digit be x and one's digit be y.

Given that, the digit at the tens place is twice that of the digit at units place.

As per given condition,

→ x = 2y .....................(1)

18 is subtracted from the number, the digits are reversed.

• Original Number = 10x + y
• Reversed Number = 10y + x

As per given condition,

→ 10x + y - 18 = 10y + x

→ 10x - x + y - 10y = 18

→ 9x - 9y = 18

→ x - y = 2 .................(2)

Substitute value of (1) in (2)

→ 2y - y = 2

→ y = 2

Substitute value of y in (1)

→ x = 2(2)

→ x = 4

Hence, the

• Original Number = 10x + y = 10(4) + 2 = 42
• Reversed Number = 10y + x = 10(2) + 4 = 24