Quote:
Originally Posted by ravian156
A train travels at an average speed of 20 mph through urban areas, 50 mph
through suburban areas, and 75 mph through rural areas. If a trip consists of
traveling half an hour through urban areas, 3-1/2 hours through suburban areas,
and 3 hours through rural areas, what is the train’s average speed for the entire
trip?
a. 50 mph
b. 53-2/7 mph
c. 54-3/7 mph
d. 58-4/7 mph
e. 59-2/7 mph
can any one tell how to solve it?
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Very easy..
Use weighted average method
20(0.5)+ 50(3.5)+75(3) = 410
sum of all the weights = 0.5+3.5+3 = 7
now divide 410 by sum of all weights = 410/7 = 58-4/7
Answer = Option..D= 58-4/7