Out of a total number of 14 files, one is always selected, so we are left with 13 files and out of these only 6 are to be chosen because one has already been selected. Thus number of ways will be 13C6.

One paramedic is to be selected from 5 paramedics and 1 technician is to be selected from 4 technicians for each team.

Number of total combinations = 5C1 x 4C1 = 5 x 4 = 20

In such problems, when we need to find the next meeting of two or more people when they both have different time periods, we find the LCM of the time periods.

Thus, Sudhir and Sushil will meet after (LCM of 64 and 72) days.

2 64, 72

2 32, 36

2 16, 18

2 8, 9

2 4, 9

3 2, 9

2, 3

LCM = 2 x 2 x 2 x 2 x 2 x 2 x 3 x 3 = 576

Thus they will meet after 576 days.

Total distance = 3000 feet

Speed = 40 feet/ minute

Time = 300040⁄ = 75 minutes

LCM of 30, 60, 90 , 105 = 540mins = 9 hrs

Beep at = 9 pm