To answer this question, you need to know that a quarter is worth $0.25 and dimes worth $0.10. In this case, the total number of money that made from quarters and dimes is $2.80
With Q=quarter and D=dime, then the equation should be:
2.80= 0.25 Q + 0.10 D
The condition that needs to be fulfilled in this case is that the quarter should be 8 more than dimes. Then you need to find out the highest possible number of the quarter and lowest possible number of the dimes.
If you divide 2.8 with 0.25 you will found it will be 11.2 but 11 quarter will result with 0.05 value which you cannot remove, so the highest possible of the quarter should be 10.
If the highest possible of the quarter is 10, then the lowest possible of dimes should be:
2.8= 0.25(10) + 0.10D
0.10D= 0.3
D=3
Since 10-3 is 7, then it is not possible for the quarter to be 8 more than the dimes.
Answer:
The average velocity the entire trip was 43.25 mi/h
Step-by-step explanation:
In this case we have to calculate an average based on the miles traveled. First we have to calculate the total of miles traveled, then calculate the portion of the total travel of each and with this calculate the average speed during the trip. First the total miles traveled:

Now the percentages:
At 57 mi/h were 
At 44 mi/h were 
At 37.8 mi/h were 
Now multiplying the speed by the portion and summing them we can have the average velocity:

The average velocity the entire trip was 43.25 mi/h
49 divided by 369 is 0.13279133 and 369 divided by 49 is 7.53061224