Question

A professor gives his students the choice of 7 assignments .

Each student has to complete 4 of the 7 assignments .
How many combinations of the 4 assignments are possible !
A 11
B 45
C 28
D 35

Answer 1

( 45 - B ) Hope I Helped

Answer 2

Answer: 35

Explanation:

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

7C4 = 7!/(7-4)!4!

=7 × 6 × 5 ×4! / 3!4!

4! at the numerator will cancel that of the denominator

= 7×6×5 / 3!

=7×6×5 / 3×2

= 7×6×5 / 6

the 6 at the numarator will cancel that of the denominator

=7×5

=35

Therefore; 7C4 = 35