Mathematics

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

2 Answer

  • ( 45 - B ) Hope I Helped
  • Answer: 35

    Step-by-step 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

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