Answer:
The speed of the current is 2 miles per hours
Step-by-step explanation:
Given as :
The speed of motorboat = x = 15 miles per hour
The time taken by motorboat trip upstream = 51 minutes
The time taken by motorboat trip downstream = 39 minutes
Let The speed of the current = y miles per hour
Let The total distance cover = A miles
So ,
Speed =
So, x - y =
I.e 15 - y =
And x + y =
I.e 15 + y =
=
I.e =
Or, 17 × (x - y) = 13 × (x + y)
Or, 17 x - 17 y = 13 x + 13 y
Or, 17 x - 13 x = 13 y + 17 y
Or, 4 x = 30 y
Now, ∵ x = 15 miles per hour
So, 4 × 15 = 30 y
Or, y =
∴ y = 2 miles per hour
Hence The speed of the current is 2 miles per hours Answer