Let's define variables:
s = original speed
s + 12 = faster speed
The time for the half of the route is:
60 / s
The time for the second half of the route is:
60 / (s + 12)
The equation for the time of the trip is:
60 / s + 60 / (s + 12) + 1/6 = 120 / s
Where,
1/6: held up for 10 minutes (in hours).
Rewriting the equation we have:
6s (60) + s (s + 12) = 60 * 6 (s + 12)
360s + s ^ 2 + 12s = 360s + 4320
s ^ 2 + 12s = 4320
s ^ 2 + 12s - 4320 = 0
We factor the equation:
(s + 72) (s-60) = 0
We take the positive root so that the problem makes physical sense.
s = 60 Km / h
Answer:
The original speed of the train before it was held up is:
s = 60 Km / h
Answer:
432 characters
Step-by-step explanation:
First we can convert 12 characters per inch in to characters per feet. Knowing that there are 12 inches per foot we know we have to multiply the 12 characters per inch by 12, giving us 144 characters per foot. Now we have to convert characters per foot to characters per yard. Knowing there are 3 feet per yard we know we have to multiply 144 characters per foot by 3, giving us a final answer of 432 characters per yard of text.
