Sail E0 Webinar
Question


What is the remainder when p - q is divided by 100, if p=299+499+699+899+.........+10099 and q=199+399+599+799+..........+9999?


Options:
A .   50
B .   10
C .   20
D .   30
Answer: Option A
:
A
99=4k+3
Thus, if you take the individual differences (upto 10)
For (299+499+699+899+1099)(199+399+599+799+999)
Last digit of this expression = (8+4+6+2+0) -(1+7+5+3+9) = -5 = 5 (10-5)
However, since there are 10 such groups; (since 1099 or multiples of 1099 are exactly divisible by 100)
=5×10=50 (which will always end in zero)

Thus the remainder when divided by 100 is the last two digits = 50 itself



Was this answer helpful ?
Next Question

Submit Solution

Your email address will not be published. Required fields are marked *

More Questions on This Topic :


Latest Videos

Latest Test Papers