Question

Your English teacher has given you a list of 10 possible topics for essays. You need to pick four topics from the list to write about over the school year. How many different groups of four essay topics can you choose?

Answer 1

210.

Explanation:

Its Combination so

10C4

= 10! / 4! (10-4)!

(10-4) = 6!

= 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 divided by

4 x 3 x 2 x 1 6 x 5 x 4 x 3 x 2 x 1

cross all the common factors

= 10 x 9 x 8 x 7 / 4 x 3 x 2 x 1 multiply those

5040 / 24 = 210 different groups of four essay topics that can be chosen.

HAVE A GREAT DAY!!!

Answer 2

10-12 i think, because 10*4=40 and 12*4=48