SOLUTION: Mr Jagmohan calculated the average of 10 three digit numbers.But due to mistake he reversed the digits of a number and thus his average increased by 29.7.The difference between the

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Question 935166: Mr Jagmohan calculated the average of 10 three digit numbers.But due to mistake he reversed the digits of a number and thus his average increased by 29.7.The difference between the ubits digit and hundreds digit of that no is:
a)4 b)3 c)2 d)cant be determined
What I have tried-------->
29.7 = 100a + 10b + c - 100c - 10b - a
29.7 = 99(a - c )
a - c = 0.3
But the answer is 3 ......how ?....why?..... Confused 😖
Please help ......
Found 2 solutions by MathLover1, AnlytcPhil:
Answer by MathLover1(20850)   (Show Source): You can put this solution on YOUR website!

Since the average increased by and there were a total of numbers, it means the incorrect number was greater than the correct number.
Say, the correct number was (where , and are the digits of the digit number)
Then the incorrect number was .




So
Answer by AnlytcPhil(1806)   (Show Source): You can put this solution on YOUR website!
I think this is more complete, as it starts from scratch:

Let 100h+10t+u be the number that was reversed,

Let S = the sum of the 9 three-digit numbers that weren't reversed.

Then 

average BEFORE reversing the number = 

average AFTER reversing the number = 

We are told that



Multiply through by 10



That simplifies to



Divide through by 99





They differ by 3.

Edwin
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