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 ar
Mathematics
lt1522
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
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
2 Answer

1. User Answers Anonym
( 45  B ) Hope I Helped 
2. User Answers ummuabdallah
Answer: 35
Stepbystep explanation:
nCr = n!/(nr)!r!
7C4 = 7!/(74)!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