Determine the average speed of the current in a river if a boat moves at 20 miles/hour in still water and takes 3 hours to travel 78 miles downstream

The speed of the current in a river is 6 miles per hour

Solution:

Given that,

Speed of boat in still water = 20 miles per hour

Time taken = 3 hours

Distance downstream = 78 miles

To find: Speed of current

If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then:  

Speed downstream = (u + v) km/hr

Speed upstream = (u - v) km/hr

Therefore, speed downstream is given as:

We know that,

Speed downstream = (u + v)

26 = 20 + v

v = 26 - 20

v = 6 miles per hour

Thus speed of the current in a river is 6 miles per hour

boxplot

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.

a3+b= 60 (the amount of money you have)

we already know the cost of a=15 so replace a with $15

($15 x 3)+b=60

multiply 15 and 3 to get $45 and replace it with $45

45+b=60

and then replace b with 15 to get the total:

45+15=60

that means you have $15 left after buying 3 dictionaries.

15 divided by the cost of a map ($5) equals 3.

so you can buy 3 maps.

sorry if it was confusing!