Mbox laptop store offers a discount for purchasing series laptops. Purchases at the store can be paid in monthly installments (with equal amounts, starting from the second month) with a simple interest of per year. The down payment required is at least of the initial price, and every subsequent minimum multiple will get an interest reduction of per year, up to a maximum of per year.
In celebration of its 22nd anniversary, the store offers an installment plan without a down payment with the lowest installment interest rate. Jojo buys a series laptop for by installments. So that Jojo's monthly installment is not more than , Jojo must pay in installments at least ... times.