Question

The sum of digits of a two-digil-number is7
. If the digits
are reversed, the new numbe
decreased by 2 equals twice. The original number
Find Thenumber.​

Answer 1

Step-by-step explanation:

Let the units digit be x.

The tens digit =7−x.

Original no. =10(7−x)+x=70−9x

If digits are reversed, no. =10x+7−x=9x+7

9x+7−2=2(70−9x)

9x+5=140−18x

27x=135

x=5

Tens digit =7−5=2

Number =25

Answer 2

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Let the number be 10x + y

x + y = 7 ................(1)

10y + x -2 = 2 (10x + y)

10y + x - 2 = 20x + 2y

-19x + 8y = 2 ................(2)

From (1) x = 7 - y

-19 (7 - y) + 8y = 2

-133 + 19y + 8y = 2

27y = 135

y = 5

x = 7 - y

x = 2

Therefore the number is 25.

Hope it helps !