Please help me?!! a motorboat takes 5 hours to travel 150 Miles going Upstream. the return trip takes 3 hours going Downstream .what is the rate of the boat in still water and what is the rate of the current ?

The the rate of the motorboat in still water is 40 km/h;  the rate of the current is  10 km/h.

Step-by-step explanation:

Let  u  be the rate of the motorboat in still water (in kilometers per hour),

let  v  be the rate of the current.

Then the rate of the motorboat going downstream is  u+v  km/h,

while its rate going upstream is  u-v  km/h.

From the other side, the rate of the motorboat going downstream is  150/3=50km/h = 30 km/h.

Thus you have these two equations

   u + v = 50    (1)   (for the rate downstream),   and

   u - v = 30    (2)   (for the rate upstream).

To solve the system, add equations (1) and (2). You will get

   2u = 50 + 30 = 80;   hence,

    u           = 80/2 = 40 km/h.

Then from the equation (1),  v = 50 - u = 50 - 40 = 10 km/h.

ANSWER.  The the rate of the motorboat in still water is 40 km/h;  the rate of the current is  10 km/h.

d, x=8

step-by-step explanation:

simplifying

4x + -5 = 2x + 11

reorder the terms:

-5 + 4x = 2x + 11

reorder the terms:

-5 + 4x = 11 + 2x

solving

-5 + 4x = 11 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-5 + 4x + -2x = 11 + 2x + -2x

combine like terms: 4x + -2x = 2x

-5 + 2x = 11 + 2x + -2x

combine like terms: 2x + -2x = 0

-5 + 2x = 11 + 0

-5 + 2x = 11

add '5' to each side of the equation.

-5 + 5 + 2x = 11 + 5

combine like terms: -5 + 5 = 0

0 + 2x = 11 + 5

2x = 11 + 5

combine like terms: 11 + 5 = 16

2x = 16

divide each side by '2'.