pappueshwar wrote:The elevator in an eleven-story office building travels at the rate of one floor per 1/4 minute, which allows time for picking up and discharging passengers. At the main floor and at the top floor, the operator stops for 1 minute. How many complete trips will an operator make during a 7-hour period?

A) 88
B) 56
C) 42
D) 60
E) 64

OA IS D. pls assist

FOR the first complete trip time taken=10/4+1+10/4=6 min

for second trip= 1+10/4+10/4+1=7 min
for third=7 and so on

let there be x no of 7 min trips,

then

6+7x=7*60
x=59.14

hence total complete trips of 7 min= 59
hence total trips = 7 min trips+6 min trip=59+1=60

hence D

pappueshwar wrote:The elevator in an eleven-story office building travels at the rate of one floor per 1/4 minute, which allows time for picking up and discharging passengers. At the main floor and at the top floor, the operator stops for 1 minute. How many complete trips will an operator make during a 7-hour period?

A) 88
B) 56
C) 42
D) 60
E) 64

OA IS D. pls assist

10 floors are passed on the way up (floors 2-11), and 10 floors passed on the way down (floors 10-1).
Thus, 1 complete trip = 20 floors.
At a rate of 1/4 minute per floor, the time for 20 floors = 20/4 = 5 minutes.
Since there is a 1-minute stop at the top and a 1-minute stop at the bottom, the total time per trip = 5+1+1 = 7 minutes.
In 7 hours -- which is 420 minutes -- the number of trips = 420/7 = 60.

The correct answer is D.

pappueshwar wrote:The elevator in an eleven-story office building travels at the rate of one floor per 1/4 minute, which allows time for picking up and discharging passengers. At the main floor and at the top floor, the operator stops for 1 minute. How many complete trips will an operator make during a 7-hour period?

A) 88
B) 56
C) 42
D) 60
E) 64

We are given that an elevator takes 1/4 minute to travel between floors and that it stops for one minute at the top floor and also on the main floor. Since the elevator is traveling from the main floor to the 11th floor, it's traveling 10 total floors.

Thus, the total time it takes for the elevator to go from the bottom floor to the 11th floor and back down is:

20 x 1/4 = 5 minutes

Since the elevator stops for a minute each at the top and main floors, the amount of time to complete a trip is:

5 + 2 = 7 minutes = 7/60 hours

Thus, in 7 hours the elevator can complete 7/(7/60) = 60 trips.

Answer: D