Let the boat speed in still water be b.
Let the current speed be c.
The speed going upstream is 20/4 = 5 mph.
The speed going downstream is 32/4 = 8 mph.
b - c = 5 ........(1)
b + c = 8 .......(2)
Adding equations (1) and (2) we get:
2b = 13
b = 13/2 = 6.5
Plugging in the value for b into equation (1) we find c = 1.5.
The boat speed in still water is 6.5 mph and the current speed is 1.5 mph.
Answer:

Step-by-step explanation:
hope it's helpful
<span>
-4c - 11 = 4c +21 add 4c to both sides
</span>
<span>
-4c - 11 + 4c = 4c + 21 + 4c simplify
- 11 = 8c + 21</span> <span> subtract 21 from both sides
- 11 - 21 = 8c + 21 - 21 </span><span>simplify
- 32 = 8c divide both sides by 8
c = - 4That's it
</span>
I hope you got
the idea
Answer: 14
Step-by-step explanation:
Given
Excavation cone measures
height 
Diameter 
Truck can dump
at a time
The volume of a cone is

Putting values

No of trips(N) required to accumulate this much volume is given by

Therefore, 14 trips are necessary to accumulate a cone of volume 