What is the answer to 3z−6/7−2z = 1.2/3.2 ? Please help

The product of two negative rational numbers is always zero sometimes zero never zero

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!

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?