Mathematics 9709 · AS & A Level · Permutations and combinations

Permutations and combinations — practice question

Within a group of 25 athletes, the numbers are 8 sprinters, 5 hurdlers and 12 throwers.
(a)[4]

Calculate the number of distinct ways to choose a team of 6 athletes if it contains at least 3 sprinters, no more than 2 hurdlers and no more than 1 thrower.

(b)[3]

From the group of 25 athletes, a set of 8 athletes is made up of 1 sprinter, 3 hurdlers and 4 throwers. These 8 athletes are then arranged in a line. How many distinct arrangements of the 8 athletes are possible if the 3 hurdlers are not all adjacent?

(c)[3]

How many different arrangements of the 8 athletes are there in which every pair of hurdlers has at least two athletes between them?

Worked solution & mark scheme

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