Answer:
c
Step-by-step explanation:
its right
Answer:
10 hours 500 miles
8 hours 270 miles
_________________
18 hours 770 miles
Average speed: 770 / 18 = 42.77;
Step-by-step explanation:
If 
is a number that is both divisible by 4 and 5, then
4 and 5 are coprime, so we can use the Chinese remainder theorem to solve this system and find that 
is a solution to the system, where 
is any integer. Simply put, any multiple of 20 fits the bill.
Now, there are 11 numbers between 100 and 300 that are divisible by 20 (100, 120, 140, and so on). We have 
when 
, so the sum we want to compute is
