A motorboat travels 102 miles in 3 hours going upstream. It travels 186 miles going downstream in the same amount of time. What is the rate of the boat in still water and what is the rate of the current?

Rate of the boat in still water:

Rate of the current:

Rate in still water = 48 mph.

Rate of current = 14 mph.

Step-by-step explanation:

Let the rate in still water be x and rate of the current be y miles per hour.

Upstream:

x - y = 102/3

Downstream:

x + y = 186/3

Adding the 2 equations

2x = 102/3 + 186/3 = 34 + 62

2x = 96

x = 48 mph.

So 48 - y = 34

y = 48 - 34 = 14 mph.

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9