The lenght of a rectangle is 27 cm and its width is 15 cm. *

Ateacher brought a pack of 17 batteries . each calculator uses 3 batteries . how many calculator can the teacher fill with batteries

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?

How many four digit even numbers can be formed from digits 1,2,3,4,5 if repetition is allowed. how can solve this using permutation formula