Iasked this question 4 times me : (( : (( : (( : (( : ((

12 students to 1 adult is the same as 36:3 and 60:5

12*3 is 36

1*3 is 3

there is your relationship between the 12 to 1 and 36 to 3

12*5 is 60

1*5 is 5 that is the relation between the 12 to 1 and 60 to 5

Let's find the remaining distance they must travel.

Total distance-distance covered
150-60=90 mi

Now, we need to find the average speed they need to travel per hour to reach the destination in 2.5 (2 1/2) hours.

90 mi/2.5 h=36 mi/h

They must travel at an average speed of 36mph to reach their destination in 2 1/2 hours.

Check:
60+36(2.5)
=120 mi