Question 8
a) Books are on sale for \(\text{\$7}\). Peter has \(\text{\$30}\) in his wallet. How many books can he buy?
b) A resting dolphin needs to take a breath 3 times a minute. How many minutes would it take to make 40 breaths?
c) A snail has fallen in a 10 feet deep hole. It started climbing up - every day it would climb 3 feet up but then it would fall 2 feet down while sleeping during the night. After how many days will the snail climb out of the hole?
Self-study timing and input convention (editorial): for part (b), assume evenly spaced breaths, with the first counted breath after 20 seconds. Enter three numbers separated by semicolons in order a;b;c: books; elapsed seconds for (b); days. The solution also expresses (b) in the minutes requested originally.
**Editorial input note:** Use no spaces before or after semicolons.
b) A resting dolphin needs to take a breath 3 times a minute. How many minutes would it take to make 40 breaths?
c) A snail has fallen in a 10 feet deep hole. It started climbing up - every day it would climb 3 feet up but then it would fall 2 feet down while sleeping during the night. After how many days will the snail climb out of the hole?
Self-study timing and input convention (editorial): for part (b), assume evenly spaced breaths, with the first counted breath after 20 seconds. Enter three numbers separated by semicolons in order a;b;c: books; elapsed seconds for (b); days. The solution also expresses (b) in the minutes requested originally.
**Editorial input note:** Use no spaces before or after semicolons.