The speed of motorboat is 36 kmph and speed of current is 4 kmph.
Step-by-step explanation:
Distance covered in 4 hours = 160 km
Time took on return trip = 5 hours
Let,
x represent the speed of boat.
y represent the speed of current.
Combined speed of boat and current when in same direction = x+y
Speed of boat and current when travelling against = x-y
Distance = Speed * Time
Speed = 
x+y = 
x+y = 40 Eqn 1
x-y = 
x-y = 32 Eqn 2
Adding Eqn 1 and Eqn 2

Dividing both sides by 2

Putting x=36 in Eqn 1

The speed of motorboat is 36 kmph and speed of current is 4 kmph.
Keywords: linear equation, addition
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A) 154 because it's an even number
You can fir 8x8x8 cubes in the carton, that means you can fit 512 cubes in the carton.
the total cost would be, 0.25 x 512 = $128
A = p(1 + r)^t
A = 6000(1 + .07)^8
A = 6000(1.07)^8
A = 10,309.12
The amount in the account after 8 years is 10,309.12, subtract the amount of principle, and you will get the amount of interest earned.
10,309.12 - 6,000 = $4,309.12
Interest $ 4,309.12