How do i calculate the loan insurance cost ?

Anusha and Naveen are planning to buy their first home.They have saved $30,000 and will withdraw the maximum from their RRSPs under the Home Buyers' Plan.They will pay the cost of CMHC mortgage loan insurance separately.They estimate closing costs at $8,200 and will take a 25-year mortgage at a rate of 3.2%, compounded semi-annually, for a 3-year term.They will pay the mortgage monthly.The home they wish to buy costs $450,000.

I KNOW THAT I NEED TO KNOW THE PURCHACE PRICE WICH IS : 450 000

THE DOWN PAYEMENT WITCH IS 55 000$

AND THE AMORTISATION PERIOD WICH IS 25 . BUT HOW DO I CALCULATE THE RATE I DONT KNOW ? IS THERE A FORMULA I CAN USE jQuery20006796636972026799_1527805234253?