The museum of science in boston has an exhibit in which metal balls drop down a chute, bounce around, and wind up in one of 21 bins. after 1000 balls have dropped, the heights within the bins clearly follow a bell-shaped curve. if the standard deviation is 3 bins, approximately how many balls are in bins 1 through 7?

a) 100
b) 160
c) 50
c) 330

It is saturday morning and jeremy has discovered he has a leak coming from the water heater in his attic. since plumbers charge extra to come out on the weekends, jeremy is planning to use buckets to catch the dripping water. he places a bucket under the drip and steps outside to walk the dog. in half an hour the bucket is 1/5 of the way full. what is the rate at which the water is leaking per hour?