Solve.
-A speedboat moves at a rate of 24 km/hr in still water. How long will it take someone to ride the boat 87 km downstream if the river's current moves at a rate of 5 km/hr?
A)0.3 hr
B)2523 hr
C)3 hr
D)4 hr

Question

Quizplus · Accepted Answer

The speedboat's speed downstream will be the sum of its speed in still water and the speed of the current, which is:
24 km/hr + 5 km/hr = 29 km/hr

Using the formula distance = speed x time, we can solve for the time it will take to travel 87 km downstream:
time = distance / speed
time = 87 km / 29 km/hr
time = 3 hours

Therefore, the answer is choice C, 3 hours. Let's denote the time it takes to ride the boat downstream as $t$. 
Since the boat is traveling downstream, we need to add the speed of the river's current to the speed of the boat to get the total speed:
$24 	ext{ km/hr} + 5 	ext{ km/hr} = 29 	ext{ km/hr}$
This means that the boat is traveling 29 km every hour downstream.
To find how long it takes for the boat to travel 87 km downstream, we divide the distance by the speed:
$ \frac{87 	ext{ km}}{29 	ext{ km/hr}} = 3 	ext{ hours}$
Therefore, the answer is C) 3 hr.

Solve. -A Speedboat Moves at a Rate of 24 Km/hr in in Still