If there are 20 steamers plying between places A and B, in how many ways could the round trip from A be made if the return was made on : the same steamer ?

If there are 20 steamers plying between places A and B, in how many ways could the round trip from A be made if the return was made on : a different steamer ?

How many selections of 4 books can be made from 8 different-books ?

From 4 mangoes, 5 oranges and 6 apples, how many selections of fruits can be made by taking at least one of them ?

Form the pair of linear equations in the following problems and find their solutions (if they exist) by any algebraic method :-Places A and B are 80 km apart from each other on a highway. A car starts from A and another from B at the same time. If they move in the same direction they meet in 8 hours , and if they move in opposite direction, they meet in 1 hour and 20 minutes respectively. Find the speed of the cars.

From 2 mangoes, 3 oranges and 4 apples, how many selections of fruits can be made by taking : at least one of them?

In how many ways can a mixed doubles game in tennis be arranged from 5 married couples, if no husband and wife play in the same game?

There are 5 routes from place A to place B and 3 routes from place B to place C. Find how many different routes are there from A to C via B.

Distance between Place A and Place B is (4x-3)km . A bus started from A and covered (3x+1)km in 1 hour. How much distance is still left to cover?