Final answer:
Sarah jumps an average of 20 times in 15 seconds, so her jumping rate is 80 jumps per minute.
Step-by-step explanation:
Sarah jumps rope an average of 20 times in 15 seconds. To find her jumping rate per minute, we can use the formula:
Jumping rate = (number of jumps) / (time in minutes)
Since there are 60 seconds in a minute, we can convert the time to minutes by dividing 15 seconds by 60.
Jumping rate = 20 / (15/60) = 20 / 0.25 = 80 jumps per minute