Factorise x^2 + x - 12
2 answers:
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Answer:
(i). Average speed = 75 km per hour
(ii). Average speed = 75 km per hour
Step-by-step explanation:
This question is incomplete; here is the complete question.
A train traveled from station A to station B at an average speed of 80 kilometers per hour and then from station B to station C at an average of 60 kilometers per hour. If the train did not stop at station b, what was the average speed at which the train traveled from station A to C?
(i). The distance that the train traveled from station A to station B was 4 times the distance that train traveled from station B to station C.
(ii). The amount of time it took to the train to travel from station A to station B is 3 times the amount of time that it took the train to travel from station B to station C.
(i) Let the distance between station B and station C = x km
So the distance between Station A and station B = 4x km
Therefore, time to travel the distance x km with 80 km per hour =
=
Similarly time taken to travel between station B and station C with speed 60 km per hour = km per hour
Now average speed between station A and station C =
=
=
=
= 75 km per hour
(ii). Let the train took the time to cover the distance between station B and station C = t hours
Therefore, time taken by the train between station A and B = 3t
Distance between Station A and station B = Speed × time
= 80 × 3t
= 240t km
Similarly distance between station B and station C = 60 × t
= 60t
Now average speed between station A and station C =
=
= 75 km per hour