Answer: the speed of the current is 9 mph.
Step-by-step explanation:
Let x represent the speed of the current.
A boat can travel 21 mph in still water. If it travels 270 miles with the current. It means that the total speed with which the boat travelled with the current is (21 + x) mph.
Time = distance/speed
Time spent by the boat in travelling 270 miles is
270/(21 + x)
In the same length of time, it travels 108 miles against the current. It means that the total speed with which the boat travelled against the current is (21 - x) mph.
Time = distance/speed
Time spent by the boat in travelling 108 miles is
108/(21 - x)
Since the time is the same, then
270/(21 + x) = 108/(21 - x)
270(21 - x) = 108(21 + x)
5670 - 270x = 2268 - 108x
108x + 270x = 5670 - 2268
378x = 3402
x = 3402/378
x = 9
Answer:
6.4008
Step-by-step explanation:
Answer:
I dont know
Step-by-step explanation:
only doing it for points
I’m pretty sure it’s 370 bc
1 and a half hours is 80+40 (40 is half of 80)
and 2 and a half hours, so 100 for each hour.
100+100+50= 250
250+120=370!!
answer : 370 kilometers per hour
