Find the wrong number in given series.
204800, 6400, 400, 50, 12.5, 6.5, 6.25

Next number in the series 1, 50, 100, 5000, 10000, ___ is :

On simplification, 1 - 2 + 3 - 4 + 5 - 6 + 7 - 8 +  _____+ 111, we get

The sum of 21 + 22 + 23 + .....+ 50 is

On simplification 1 – 2 + 3 – 4 + 5 – 6 - - - - + 101, we get

1 + 2 + 3 +………+ 50 equals

In the following series, 17, 24, 32, 38, x, 74, y, ... what is the value of (2x + y)?