Solve each problem.
1
A biologist is studying diseases in chimpanzees. He takes three random samples of the same
size from a troop of 150 chimpanzees. One sample indicates that 3% of the chimpanzees are
hairless, another sample indicates that 5% are hairless, and a third sample indicates that 4% are
hairless. How many hairless chimpanzees should the biologist expect to find in the troop?

2
A gym teacher fills a basket with 70 balls. Some of the balls are rubber, and the rest are foam.
He has four cļasses per day. Each class gets out 10 balls at random. At the end of class, they put
the balls back in the basket for the next class to use. The first class pulls out 2 rubber balls and 8
foam balls. The second class pulls out 4 rubber balls and 6 foam balls. The third and fourth classes
both pull out 3 rubber balls and 7 foam balls. About how many of the balls in the basket are rubber?
xt Predictions: On