Heya friend,
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Let the digits at ones place be x. Then,
the digits at tens place = (8-x)
Original number = 10(8-x) + x
= 80 - 10x + x
= 80 - 9x
On interchanging the digits
new number obtained = 10x + 8-x
= 9x + 8
According to question,
New number - Original number = 18
9x + 8 - (80-9x) = 18
=> 9x + 8 - 80 + 9x = 18
=> 18x - 72 = 18
=> 18x = 18 + 72
=> 18x = 90
=> x = 90/18
=> x = 5
Hence, the digits at ones place is 5.
The digits at tens place = (8-5) = 3.
So, the original number is 35 and the new number is 53.
Thanks
The surface area would be <span>4633.95 mm</span>
