A fruit seller had some apples. He sells 40% apples and still has 420 apples. How many apples he had at the begining?
It takes 24 hours for 10 men to make 15 cakes. How many cakes can be made if 8 men work for 36 hours?
The ratio of present age of father, mother and son is 7:5:3. The sum of their ages is 75. What is the present age of the son in years?
How many prime numbers are there between 1 to 11?
What is the smallest positive integer that is evenly disvible by both 21 and 9?