Spigot A takes 240 minutes to fill an aquarium. Spigot B takes 80 minutes to fill the same aquarium. Spigot C only takes 20 minutes to fill the aquarium. If all three Spigots were used together, how many seconds would it take to fill the aquarium?
If Scarlett mows her yard in 2 hours and her sister Amelia can mow the yard in 3 hours, then how long will it take them working together to mow the yard?
Anthony is depositing money into a bank account. After 3 months, there is $147 in the account, and after 7 months, there is $343 in the account. Find the rate of change of the account.