The average of seven numbers is 18. If one of the number is 17 and if it is replaced by 31, then the average becomes: 

A car travel to a place 150 km away at an average speed of 50 km/hr and returns it 30 km/hr. What is the average speed of the whole journey?

A batsman makes a score of 87 runs in the 17^th match and thus  increases his average by 3. Find his average after 17^th match.

The average of four consecutive even numbers is 15. The 2nd highest number is: 

In an examination, 40% of the candidates write their answers in Urdu and the rest in Marathi. The average marks of the candidates writing in Urdu is 74 and the average marks of the candidates writing in Marathi is 77. What are the average marks of all the candidates? 

Find the average of the following set of numbers.
132, 148, 164, 128, 120, 136

What decimal of a week is an hour?