Question

a number consist of two digits. the digit at tens place is twice that of the digit at the unit place. if 18 is substracted from the number, the digit is reversed. find the number​

Answer 1

Answer:

The number is 42.

Step-by-step explanation:

Given :-

• A number consists of two digits.
• The digit at ten's place is twice that of the digit at the unit place.
• If 18 is substracted from the number, the digit is reversed.

To find :-

• The number.

Solution :-

Let the unit's digit of the number be x.

★ The digit at ten's place is twice that of the digit at the unit place.

Then,

• Ten's digit = 2x

The number = 10×2x + x

→The number = 20x + x

→ The number = 21x

★ If 18 is substracted from the number, the digit is reversed.

• The reversed number = 10×x + 2x = 12x

A/q,

21x-18 = 12x

$\implies$ 21x-12x = 18

$\implies$9x = 18

$\implies$x = 18/9

$\implies$x = 2

• Unit's digit = 2
• Ten's digit = 2×2 = 4

Therefore,

The number = 21 × 2 = 42

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Answer 2

AnswEr :-

• The number is 42.

Given :-

• A number consists of two digits.

• The digit at tens place is twice that of digit at the unit place.

• When 18 is subtracted from the number, the digit is reversed.

To Find :-

• That number.

SoluTion :-

Let,

• Unit's digit be x

• Ten's digit will be 2x [ ten's digit is twice of unit's place.

Number :-

• 10(2x) + x

→ 20x + x

→ 21x

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

• 10(x) + 2x

→ 10x + 2x

→ 12x

According to question :-

• 21x - 18 = 12x

→ 21x - 12x = 18

→ 9x = 18

→ x = 18/9

→ x = 2

★ Unit's digit = 2

★ Ten's digit = 2 × 2 = 4

Hence, that number is 42.

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