Arithmetic Reasoning

Question: A man wears socks of two colours – Black and brown. He has altogether 20 black socks and 20 brown socks in a drawer. Supposing he has to take out the socks in the dark, how many must he take out to be sure that he has a matching pair ?
[A].

3

[B].

20

[C].

39

[D].

None of these

Answer: Option A

Explanation:

Since there are socks of only two colours, so two out of any three socks must always be of the same colour.

Question: A bird shooter was askgd how many birds he had in the bag. He replied that there were all sparrows but six, all pigeons but six, and all ducks but six. How many birds he had in the bag in all?
[A].

9

[B].

18

[C].

27

[D].

36

Answer: Option A

Explanation:

There were all sparrows but six’ means that six birds were not sparrows but only pigeons and ducks.

Similarly, number of sparrows + number of ducks = 6 and number of sparrows + number of pigeons = 6.

This is possible when there are 3 sparrows, 3 pigeons and 3 ducks i.e. 9 birds in all.

Question: A shepherd had 17 sheep. All but nine died. How many was he left with ?
[A].

Nil

[B].

8

[C].

9

[D].

17

Answer: Option C

Explanation:

‘All but nine died’ means ‘All except nine died’ i.e. 9 sheep remained alive.