Question

Given the speeds of each runner below, determine who runs the fastest. \text{Debbie runs 15 feet per second.} Debbie runs 15 feet per second. \text{Liz runs 112 feet in 11 seconds.} Liz runs 112 feet in 11 seconds. \text{Stephanie runs 1 mile in 411 seconds.} Stephanie runs 1 mile in 411 seconds. \text{Tony runs 581 feet in 1 minute.} Tony runs 581 feet in 1 minute.

Answer 1

Answer:

Debbie

Step-by-step explanation:

Remember that

1 mile=5,280 ft

1 minute=60 seconds

In order to be able to compare all the speeds, we are going to unify the units to feet per second

we have

1) Debbie runs 15 feet per second

$15\frac{ft}{sec}$

2) Liz runs 112 feet in 11 seconds

Divide the distance by the time to find the unit rate

$\frac{112}{11}=10.18\frac{ft}{sec}$

3) Stephanie runs 1 mile in 411 seconds

Convert to feet per second

$\frac{1}{411}\frac{mi}{sec}=\frac{1*(5,280)}{411}=12.85\frac{ft}{sec}$

4) Tony runs 581 feet in 1 minute

Convert to feet per second

$\frac{581}{1}\frac{ft}{min}=\frac{581}{60}=9.68\frac{ft}{sec}$

therefore

The fastest is Debbie because her speed is greater than the other runners.

$15\frac{ft}{sec}>12.85\frac{ft}{sec} > 10.18\frac{ft}{sec} > 9.68\frac{ft}{sec}$

Answer 2

Answer:

Step-by-step explanation: it  is ok