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:
30°
Step-by-step explanation:
3x + (90 - 2x) = 180 - 60
x + 90 = 120
x = 120 - 90
x = 30°
Answer:
6 1/3
Step-by-step explanation:
Multiply points per visit x number of visits, using x for the number of visits:
5.5x
Add that to the points she already has:
5.5x + 60
This needs to equal a total of 104 points:
5.5x + 60 = 104
Now solve for x
5.5x + 60 = 104
Subtract 60 from both sides
5.5x = 44
Divide both sides by 5.5
X = 8
She needs 8 more visits
It would be 0.6 because dividing it would be 3/5 = 0.6
Answer is D
