At college, 70% of the students studied Maths, 75% studied English, 85% studied French and 80% studied German. What percentage at least must have studied all 4?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

What numbers should go on the bottom line?
3    6    9   15
8    2   10  12
11   8  19   27
19  10  29  39
?      ?    ?   ?

In a bouquet of flowers, all but two are roses, all but two are tulips, and all but two are daisies. How many flowers are in the bouquet?

Can you tell us the rule which is followed in the following number series?
102, 104, 108, 110, 114, 128

Find next number in sequence

81 87 69 82 84 ?

The following list follows a peculiar pattern. Can you find it out and guess the next number?
2, 12, 36, 80, 150, 252, ?

Can you find next number in tricky mathematical series below?

111 , 113 , 117 , 119 , 123 , 137 ?