Question

A math teacher needs to choose 6 students from a class of 30 to go to the library. How many different groups can she select?

Answer 1

She can select 5 different groups...
30/6=5

Hope this helps leave a 5-rate and a thanks

Answer 2

593775ways

Explanation:

Combination has to do with selection of r objects from a total number of n objects and this can be done in nCr ways. Generally,

nCr = n!/(n-r)!r!

Since the math teacher has to select 6 students from a class of 30, this can be done in 30C6 number of ways to have;

30C6 = 30!/(30-6)!6!

30C6 = 30!/24!6!

30C6 = 30×29×28×27×26×25×24!/24!×6×5×4×3×2

30C6 = 30×29×28×27×26×25/6×5×4×3×2

30C6 = 427,518,000/720

30C6 = 593775ways

This means, the selection can be made in 593775ways