Ashishmathew01081987 wrote:
Mr. Smith calculated the average of 10 " three digit numbers". But due to a mistake he reversed the digits of a number and thus his average increased by 29.7. The difference between the unit digit and hundreds digit of that number is :
a) 4
b) 3
c) 2
d) 1
e) 0
Since the average increased by 29.7 and there were a total of 10 numbers, it means the incorrect number was 297 greater than the correct number.
Say, the correct number was abc (where a, b and c are the digits of the 3 digit number)
Then the incorrect number was cba.
100c + 10b + a - (100a + 10b + c) = 297
99c - 99a = 99(c - a) = 297
297 = 99*3 = 99(c - a)
So c - a = 3
Answer (B)
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