Answer:
40
Step-by-step explanation: If 10 : 15, then 4 times both of those should be an hour. This would be 40 : 60. That is why 40 is the correct answer.
Answer: v = 2
Step-by-step explanation:
Your equation:

You can multiply both sides by 8 to eliminate the fraction, which gives you this:
6v - 5 = 7
Then, you can solve for it:
6v = 12
v = 2