Mathematics: Aboat goes 240 miles downstream in the same time it can go 160 miles upstream. the speed of the current is 5 miles per hour. what is the speed of the boat in still water?

3pi r 2 603.43 is the answer...

Aboat goes 240 miles downstream in the same time

amesha62

17.01.2022

25 mph.

Step-by-step explanation:

Le tx mph be the speed of the boat in still water. Then the speed going downstream is x+5 mph and the speed going upstream is x-5 mph.

1. A boat goes 240 miles downstream and it took it

$\dfrac{240}{x+5}\ hours.$

2. A boat goes 160 miles upstream and it took it

$\dfrac{160}{x-5}\ hours.$

Then

$\dfrac{240}{x+5}=\dfrac{160}{x-5},\\ \\240(x-5)=160(x+5),\\ \\3(x-5)=2(x+5),\\ \\3x-15=2x+10,\\ \\3x-2x=10+15,\\ \\x=25\ mph.$

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