Amotorboat can maintain a constant speed of 25 miles per hour relative to the water. the boat makes a trip upstream to a certain point in 48 minutes; the return trip takes 27 minutes. what is the speed of the current?

The speed of the current is 7 miles per hour .

Step-by-step explanation:

Given as :

The speed of motorboat = x = 25 miles per hour

The Time taken to make upstream trip = 48 minute = = 0.8 hour

And The time taken to make downstream trip = 27 minutes = = 0.45 hour

Let The speed of the current = y  miles per hour

Let The total distance cover = D miles

Now, Speed =

So , For upstream trip

x - y =

Or, D =   × ( x - y )             ........1

And , For downstream trip

x + y =

Or, D =   × ( x + y )            .......2

Now, equating the eq 1 and 2

I.e 0.8 × ( x - y ) = 0.45 × ( x + y )  

Or, 0.8 x - 0.8 y = 0.45 x + 0.45 y

Or, 0.8 x - 0.45 x = 0.8 y + 0.45 y

or, 0.35 x = 1.25 y

Now since x = 25 miles per hour

So,  0.35 × 25 = 1.25 y

or, y =

∴ y = 7

So, The speed of current = 7 miles per hour

Hence The speed of the current is 7 miles per hour . Answer

-12 > a

step-by-step explanation:

-11 > 1 + a

subtract 1 from each side

-11-1 > 1-1+a

-12 > a