Question

Use the formula D=rt where D is distance, r is rate, and t is time.
The distance is 40
Julio finishes the 40 yd dash in 4.39 seconds. Rich finishes it at 6.18 seconds

1. Solve D=rt for rate. (1 pt)
D/t=r

2. Use the statistics given in Act Two and your equation from #1. Statistics shown above.
a. At what speed (rate) does Rich run the 40-yard dash? (1 pt)
40/6.18=6.47


b. At what speed (rate) does Julio run the 40-yard dash? (1 pt)
40/4.39=9.11


c. Solve D=rt for time. How long does it take Rich to run with a 10-yard lead? (1 pt)
D(r)=t.
40-10=30yards
30(6.47)=194.1
d. How long does it take Julio to run the 40-yard dash at half-speed? Who will win? (2 pts)
Help

3. If both runners are at full speed, how many yards of a head start will Rich need to win? (2 pts)
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4. Write and solve your own question using this scenario. (Remember to show all work!) (2 pts)
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Answer 1

yikes c.
if D = r t
then t = D/r (you KNOW that :)
30 yards/6.47 yards/sec = 4.64 sec
You KNOW it would not take him 194 seconds !!!!


d.
Julio runs at 9.11/2
= 4.555 yards/second
40 yards/ 4.555 yards/sec =8.78 seconds
Which you already know is TWICE as long because half the speed :)

now head start
Julio took 4.39 seconds
How far can Rich go in 4.39 seconds?
4.39 * 6.47 = 28.4 yards
40 - 28.4 = 11.6 yards head start to tie

Answer 2

Omg thankyou. XD I dont know why I was having such a hard time with this