Question

Operations: Housekeeping Math Quiz

Answer 1

Answer:

Total time = 63 hours

Step-by-step explanation:

First, let us write out the information in the question:

rate at which rooms are cleaned = 20 mins/room

number of rooms = 175

one-fifth of the rooms take 40% longer to clean

Next, let us convert the extra time taken to clean the rooms from percentage to time.

40% of normal cleaning time = 40% of 20

= 40/100 × 20 = 0.4 × 20 = 8 minutes

∴ onw-fifth of the rooms take an extra 8 minutes = 28 minutes in total

Next, let us calculate how many of those rooms in the total 175 takes the extra cleaning time:

one-fifth of the rooms takes 28 minutes to clean means that:

1 in every 5 rooms out of the 175 rooms take 28 minutes to clean

∴ Number of rooms with extra cleaning time = 1/5 of 175

= 1/5 × 175 = 0.2 × 175 = 35

∴ 35 rooms take 28 minutes each to be cleaned.

Now let us calculate the total cleaning time:

if 35 rooms take the extra cleaning time, then the number of rooms that have the normal cleaning time is as follows:

175 - 35 = 140

Total time:

140 rooms taking 20 minutes per room = 140 × 20 = 2,800 munites

35 rooms taking 28 minutes per room = 35 × 28 = 980 minutes

Total cleaning time = 2800 + 980 = 3780 minutes

converting to hours (1 hour = 60 minutes)

∴ 3780 minutes = 3780 ÷ 60 = 63 hours (2 days and 15 hours)