The tens digit is three less than the units digit.

Ответ:

syrai7404

28.01.2022

Original number is 47

Step-by-step explanation:

Given: The tens digit is three less than the units digit. If the digits are reversed, the sum of the reversed number and the original number is 121.

To find: the original number

Solution:

Let x denotes digit at ones place.

As the tens digit is three less than the units digit,

Digit at tens place = x-3

Original number = 10(x-3)+x=11x-30

When digits are reversed,

Reversed number = 10x+(x-3)=11x-3

As the sum of the reversed number and the original number is 121,

$11x-30+11x-3=121\\22x-33=121\\22x=154\\x=\frac{154}{22}\\=7$

So,

original number = 11x-30=11(7)-30=77-30=47

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