Answer:
100 boxes
Explanation:
Time difference between 3:30pm and 1:00 pm is 2 hours 30 mins or 2.5 hours.
Boxes loaded between this duration are 65-40=25 boxes
Rate of loading boxes are 24/2.5=10 boxes per hour.
Time difference between 7pm and 1 pm is 7-1=6 hours
Initial boxes unloaded (by 1 pm)= 40 boxes
For 6 hours, using the rate of 10 boxes per hour, unloaded boxes will be 6*10=60 boxes
Total boxes will be 60+40=100 boxes
By 7pm of the same day, 100 boxes will be unloaded.