Over a period of 5 days, the average time on a train from one town to a city is 77 minutes. One trip was 71 mins, another was 74 mins and two each were 78 mins. How many mins long was the fifth trip?

Question

anonymous · Answer

I guess they want you to find the length of the fifth train ride such that it makes the average of the 5 equal to 77 mins.

For the average:
(71 + 74 + 78 + 78 + x)/5

The question says it equals 77mins:

77 = (71 + 74 + 78 + 78 + x)/5

Solve for x.