Its original quantity is 10 in the new quantity is 3 what is the percent decrease

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!

Leslie started last week with $1200 in her checking account. during the week, she wrote the checks below.

How can (square root of 25) ^2 be rewritten?