A, B , C can finish a work in 10, 12, and 15 days respectively. They start working together. If B stops after 2 days, how long would it take A and C to finish the remaining work

Raju ate $$3\over 8$$part of a pizza and Adam ate $$3\over 10$$ part of the remaining pizza. Then Renu ate $$4\over 7$$ part of the pizza that was left. What fraction of the pizza is still left?

What number must be subtracted from each of the numbers 55, 23, 43 and 19, so that the new values are in proportion? 

A solid metallic cylinder of base radius 5 cm and height 7 cm is melted to form cones, each of height 1 cm and base radius 1 mm. Find the number of cones?

The average of 30 numbers is 15. The average of the first 18 numbers is 10 and that of the next 11 numbers is 20. The last number is

4/5 of a number is 10 more than two-thirds of the same number. What is that number?

A pump can fill a cistern in 40 minutes and another pump can empty the filled up cistern in 1 hour. By mistake, without closing the second pump, the first pump is opened. The time in which the empty cistern will be filled up is

2x + 4y – 8xy -1 =?