One hose can fill a goldfish pond in 24 ​minutes, and two hoses can fill the same pond in 15 minutes. Find how long it takes the second hose alone to fill the pond

Dakota earned $7.50 in interest in account a and $18.75 in interest in account b after 15 months. if the simple interest rate is 4% for account a and 5% for account b, which account has the greater principal? explain. to make it a little easier, there is an image. good luck!