What’s the answer to this question need help

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50.

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?