What is the percentage increase if a savings account grew from $200 to $275

What is the rate of change of a line that passes through (2,-5) and (6,-2)?

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?

Cody was 165cm tall on the first day of school this year, which was 10% taller than he was on the first day of school last year.