[Question]Sarah's external drive showed 2.4 gigabytes free and 12.6 gigabytes used. She decided to delete a folder of size 4.6 gigabytes and store new files of 2 gigabytes. If she will transfer all her files to a new external drive of size 20 gigabytes, how many free gigabytes will the new external drive have?
[Answer]There were 12.6 - 4.6 = 8 gigabytes used after deleting some files. Then, the used space went up to 8 + 2 = 10 gigabytes after storing other files. Thus, the new 20 gigabytes external drive will have 20 - 10 = 10 gigabytes free. The answer is 10.

[Question]Jimmy and Tonya both like collecting matchbooks and stamps. Tonya and Jimmy decide to trade some stamps and matchbooks. They have each decided that one stamp is worth 12 matches. Each matchbook contains 24 matches. If Tonya arrives with 13 stamps, Jimmy has 5 matchbooks, and Jimmy trades all his matchbooks for stamps, how many stamps does Tonya have left?
[Answer]Jimmy has 120 matches because 5 times 24 equals 120. Jimmy trades this for 10 stamps because 120 divided by 12 equals 10. Tonya has 3 stamps left because 13 minus 10 equals 3. The answer is 3.

[Question]9 years from now, John will be 3 times as old as he was 11 years ago. How old is he now?
[Answer]Let J represent John's age. We have J + 9 = 3(j 11). So, J + 9 = 3J 33. So, 9 = 2J 33. So, 42 = 2J. Which means that John's age is J = 42 / 2 = 21. The answer is 21.

[Question]Janelle had 26 green marbles. Then she bought 6 bags of blue marbles. There were 10 marbles in each bag. She created a gift of 6 green marbles and 8 blue marbles and gave it to a friend. How many marbles does Janelle have now?
[Answer]
Janelle has 6 bags * 10 blue marbles = 60 marbles. Janelle has a total of 26 green marbles + 60 blue marbles = 86 marbles. Janelle gave away a gift of 6 green + 8 blue marbles = 14 marbles. Janelle has a final amount of 86 marbles - 14 marbles = 72 marbles. The answer is 72.