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A train travelling at a speed of 75 mph enters a tunnel 31/2 miles long

A train travelling at a speed of 75 mph enters a tunnel 31/2 miles long. The train is 1/4mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?
A.2.5 minB.3 min
C.3.2 minD.3.5 min

Answer: Option B
Explanation:
Total distance covered
=(7+1(miles
24
=15miles.
4
Therefore Time taken
=(15(hrs
4 x 75
=1hrs
20
=(1x 60(min.
20
= 3 min.

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The telephone bill of a certain establishment is party fixed and partly varies as the number of calls consumed. When in a certain month 540 calls made the bill is Rs.1800. In another month 620 calls are consumed then the bill becomes Rs.2040. In another month 500 units are consumed due to more holidays. The bill for that month would be :

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