Question

A certain number between 10 and 100 is 8 times the sum of its digits. If 45 is subtracted from it the digit
be reversed. Find the number.(ANSWER:72)

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Answer 1

Answer!!

1. 10x+y = 8(x+y)

10x+y =8x+8y

2x-7y=0

10x+y-45 = 10y+x

2. 9x-9y=45 x-y = 5

multiply by -2

-2x+2y=-10

add to (1)

-5y=-10

3. y=2

x-y =5

x=7

= 72