How do you solve this problem? what are the steps? what to do?

How many times larger is 6 × 10^12 than 2 × 10^7? a. 30,000 b. 3,000 c. 3,000,000 d. 300,000

Mikes car gets an average of 28 mpg. there are 12 gallons of fuel in mikes car when he starts his trip of 140 miles. about how many gallons are left at the end of his trip?

Taber invested money in an account where interest is compounded every year. he made no withdrawals or deposits. the function a(t)=525(1+0.05)^t represent the amount of money in the account after t years. how much money did taber origanally invested?