Answer: Fraction of twins =
Fractions of triplets =
Fractions of quadruplets = 
Step-by-step explanation:
Since we have given that
Number of set of twins = 5
Number of sets of triplets = 2
Number of sets of quadruplets = 1
Total number of sets is given by

Now, we need to find the fraction of those students.
So, Fraction of twins is given by

Fractions of triplets is given by

Fractions of quadruplets is given by

Answer:
24 mph for both 60 miles and 40 miles.
Step-by-step explanation:
We need to find how long it takes to get to college and from it.
Speed x time (x) = Distance (60)
30x = 60
x=2
It takes two hours to get to college
20x = 60
x = 3
It takes 3 hours to get back. It's a total of 5 hours, 2 hours at 30mph and 3 at 20. Now we need to find the average
30+30+20+20+20=120
120/5= 24
The average speed for the round trip is 24.
To do the second part, we follow the same process, but replace 60 with 40 for distance.
30x=40
x= 1.33
20x=40
x=2
We can add the total distance and divide by total time to find the average.
The total distance is 80. Time is 3.33
80/3.33=24
The average speed is still 24.