The average of three numbers is 40. The first number is twice the second and the second one is thrice the third number. The difference between the largest and the smallest numbers is

What should come in place of the question mark '?' in the following number series?

77, 76, 84, 57, ?, – 4

The average temperature of Monday, Tuesday, Wednesday and Thursday is 60°. The average temperature for Tuesday, Wednesday, Thursday and Friday is 63°. If the ratio of temperature for Monday and Friday is 21 : 25, then what is the temperature of Friday ? 

A drug dealer sells a tablet for 5 rupees. If he buys a tablet packet for Rs 50 and if a tablet packet contains 25 tablets, what will be his profit percentage?

A and B can together complete a piece of work in 18 days. B and C can together complete the same work in 24 days and A and C can together complete it in 36 days. In how many days can A. B and C, working together, complete this piece of work?

In a ∆ABC ∠A : ∠B : ∠C  = 2 : 3 : 4 . A line CD drawn || to AB, then the ∠ACD is: 

A man is walking at a speed of 12 km / h. After every kilometer he relaxes for 4 minutes. How much time (in minutes) will it take to cover a distance of 8 kilometers?

Five years ago, the average age of 4 girls was 7 years. On joining a new girl, the present average age becomes 13 years. The current age of the new girl is: