Question

William sunk 75% of the shots he made on the basket. If he threw 160 shots, how many did he miss?

Answer 1

Let X be the number of successes in n independent repetitions of a random experiment have probability of success = 0.75

$$p={X \over n}$$

Let Y be the number of misses in n independent repetitions. Then

$$X+Y=n$$

$$Y=n-X=n-np=n(1-p)$$

If William threw 160 shots, he did , how many did he miss?

$$Y=160(1-0.75)=40$$

William did 40 misses.