Solution:

120

Explanation:
Let g be the grass in the beginning
r be the rate at which grass grows everyday
y be the rate at which one cow eats the grass per day
n be the number of cows to eat the grass in 96 days

g + 40*r = 40*40*y ------- 1
g + 60*r = 30*60*y ------- 2
g + n*r = 20*n*y ---------- 3

from 1 and 2 we have
r = 10y and g = 120r
using 3, we get
nr=120r
n = 120

Solution:

This is simply the numbers 2^0,2^1,2^2 ... that is 1,2,4,8,16... So for making 1000 kg we need up to 1, 2, 4, 8, 16, 32, 64, 128, and 512

Solution:

Batsman hit six and gone retired hurt while the new batsman come to play and get runout for his wicket and the other batsman hit six and made both century and team win..

Solution:

He should shoot at the ground.

If Kangwa shoots the ground, it is Rafael's turn. Rafael would rather shoot at Ferdinand than Kangwa, because he is better.
If Rafael kills Ferdinand, it is just Kangwa and Rafael left, giving Kangwa a fair chance of winning.
If Rafael does not kill Ferdinand, it is Ferdinand's turn. He would rather shoot at Rafael and will definitely kill him. Even though it is now Kangwa against Ferdinand, Kangwa has a better chance of winning than before.

Solution:

Playing chess

Game needs two players so Brother-8 is playing chess with Brother-2