The distance between two piers on a river is 45 miles. It takes a motorboat, moving downriver, 2 hr 15 min to complete the journey. How much time does it take the same boat to go back upstream if the current flows at 2.5 mph?

3 hours

Step-by-step explanation: we can make a variable for our answer(x)

Now, we need to find the speed of the boat without the current (y)

we can make this equation: d/t = s: 45/(y + 2.5) = 2 1/4

hence: y = 17.5

now we can substitute in the current's speed: y -2.5

17.5 - 2.5 is 15

now we can solve for x

45/15 = 3

hence, we get 3 hours as our answer

add all the numbers and check the ones place.

the answer is 486. as the ones place is more than 4, the estimation will be the next 10 ie, 490

d

step-by-step explanation: