The weights of 4 boxes are 30, 40, 50 and 80 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxes and in a combination a box can be used only once?

6 years ago, Raju's age was 2 years less than half of his brother's age, which was 20 years. What is his present age?

A man takes 6 km distance to go around the rectangular area. If the area of the rectangle is 2 sq. km. find the difference between length and breadth.

The average age of three friends A, B, C is 20 years. The average age of A and B is 19 years, then what is the age of C?

Adam who is 20 years old is 4 times as old as Mary. What will be Mary’s age when Adam is twice as old as her?

If L=+, M= - , N = ×, P=÷ then 5 N 5 P 5 L 5 M 5 =?

In an office of 50 people, 18 write with their right hand, 26 write with their left hand and 2 can write with both hands. How many cannot write?