Question

Amol takes the average of 10 two-digit numbers. By
* mistake he interchanges the digits of one no. As a result,
the average increases by 1.8 of the previous avg. If a & b
are the digits of that particular no., what is the value of (b-
a)?

Answer 1

Answer:

According to the question let as consider by mistake he writes 10th number with its digits interchanged

∴10x+y−(10y+x)10=3.6

In these remaining nine numbers are same and they cancel out

10x+y−10y−x10=3.6

9x - 9y = 36

x - y = 4