Aboy swims downstream 0.9 miles in the same amount of time that he can swim 0.6 miles upstream. if the rate of the current is 1.5 mph, how fast can he swim in still water?

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.

the answer is:

the correct option is the option b.

to calculate the surface area of the right cylinder, we need to use the following formula:

from the picture we know that:

so, substituting and calculting we have:

hence, we have that the correct option is the option b.

have a nice day!