Question

HELP:Sarah, who is 19 feet away from Justin, has a ball in her hand. Sarah throws the ball away from Justin at a speed of 5 feet per second. It takes the ball 4 seconds to reach a third friend, Brandon. When the ball reaches Brandon, how far away is it from Justin?

Answer 1

Justin is 1 feet far away from Brandon

Explanation:

As shown in the diagram, we let the distance between Justin and Brandon be x

`Speed = (distance)/(time)`

from the question

the total time taken by the ball to reach Brandson=4s

Also the total distance is travelled by the ball=19+x

while the average speed=5ft/s

By substitution we obtain

`5 = (19 + x)/(4)`

`\implies4 * 5 = 19 + x`

`\implies20=19 + x`

`\implies20 - 19 = x`

x=1 feet