We are trying to find miles/hour, which shows that we are going to be dividing the total number of miles by the total number of hours. Thus, in this case, the miles/hour rate will be:

He drove 40 miles in one hour.
60 = (10 + 20 + 30 + 40 + x)/5
300 = 100 + x
x = 200
Answer: 200
The answer is 21/6
Explanation: the next number in the pattern would be 21 since this is linear
Answer:
-525 feet
Step-by-step explanation:
If a submarine was below sea level, that would mean that it would be at an elevation of negative feet down, so if it's 800 feet below sea level, it's elevation would be -800.
to ascend means to rise, so the submarine would be moving +275 feet (going higher, closer to sea level)
so you can make out this equation: -800 + 275
this would equal: -525