A mason has made a concrete slab. He needs it to be rectangular. It what different ways can he make sure that it is rectangular?

What are the different ways in which infectious diseases can spread?

A rectangular park is to be designed whose breadth is 3 m less than its length. Its area is to be 4 square metres more than the area of a park that has already been made in the shape of an isosceles triangle with its base as the breadth of the rectangular park of an altitude 12 m. Find the length and breath of the rectangular park.

A postman has to deliver five letters to five different houses. Mischievously, he posts one letter through each door without looling to see if it is the correct address. In how many different ways could he do this so that exactly two of the five houses receive the correct letters?

A batsman scores exactly a century by hitting fours and sixes in 20 consecutive balls. In how many different ways can he do it if some balls may not yield runs and the order of boundaries and over boundaries are taken into account?

A rectangular park is to be designed whose breadth is 3 m less than its length. Its area is to be 4 square metres more than the area of a park that has already been made in the shape of an isosceles triangle with its base as the breadth of the rectangular park and of its altitude 12 m. Find length and breath of the rectangular park .

A persons has got 12 friends of whom 8 are relatives. In how many ways can he invite 7 guests such that 5 of them may be relatives ?

Bosco wishes to start a 200 m^2 rectangular vegetable garden. Since he has only 50 m barbed wire, he fences three sides of the rectangular garden letting his house compound wall act as the fourth side of the fence. Find the dimensions of the garden.