At the end of a business conference the ten people present all shake hands with each other once. How many handshakes will there be altogether ?

Answer: Option B

Explanation:

Total number of handshakes =
9+8+7+6+5+4+3+2+1 = 45

Answer: Option A

Explanation:

"All but 10 died" means all except 10 died, so he is remained with 10 sheep.

Answer: Option A

Explanation:

Seven pieces consist of 6 smaller equal pieces and one half cake piece.

Weight of each small piece = 20 gm
So, total weight of the cake = 2 (20 * 6) = 240 gm

Answer: Option A

Explanation:

The required number will be such that it leaves a reminder of 1 when divided by 2, 3 or 4 and no reminder when divided by 5. Such a number is 25 among options

Answer: Option B

Explanation:

Suppose boy got x sums right and 2x sums wrong,
then,
x+2x = 48
=> 3x = 48
=> x = 16