Tim goes on a car journey
1 answer:
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Answer:
of the distance
Step-by-step explanation:
We know that a ferry traveled of the distance between two ports in
hours.
In order to calculate what fraction of the distance between the two ports can the ferry travel in one hour we can do the following reasoning :
The rate of the ferry is the same at any time.
The ferry will travel of the distance in
hours.
If we divide each fraction by 3 ⇒
and
We do this to obtain a ''1'' in the numerator of the second fraction (the hours fraction). Now, we can say that :
The ferry will travel of the distance in
hours.
Finally, we multiply each fraction by 7 (in order to obtain the distance for 1 hour) ⇒
and
We found out that the ferry will travel of the distance in 1 hour.
Answer:
The speed of current is 7 miles per hour
Step-by-step explanation:
Given as :
The distance cover by boat in downstream = D = 147 miles
The distance cover by boat in upstream = d = 147 miles
The time taken in downstream trip = T = 7 hours
The time taken in upstream trip = t = 21 hours
Let The speed of boat in still water = x mi/h
And The speed of current = y mi/h
The speed in downstream = S = (x + y) mi/h
The speed in upstream = s = (x - y) mi/h
<u>Now, According to question</u>
∵ Distance = speed × time
<u>For downstream</u>
D = S × T
Or, 147 miles = (x + y) mi/h × 7 hours
i.e 7 (x + y) = 147
Or, x + y =
∴ x + y = 21 ........A
<u>For upstream</u>
d = s × t
Or, 147 miles = (x - y) mi/h × 21 hours
i.e 21 (x - y) = 147
Or, x - y =
∴ x - y = 7 .......B
Now, Solving equations A and B
So, (x + y) + (x - y) = 21 + 7
Or, (x + x) + (y - y) = 28
Or, 2 x + 0 = 28
∴ x =
i.e x = 14 miles per hour
The speed of boat in still water = x = 14 mi/h
Now, putting the value of x into eq B
So, y = x - 7
Or, y = 14 - 7
i.e y = 7 miles per hour
The speed of current = y = 7 mi/h
Hence, The speed of current is 7 miles per hour . Answer