Its simples Interest so dont use Compound Interest Please!

37. Jason obtained a bank loan and is expected to pay it back in three installments: $3100 in six months, $4200 in 10 months and $4800 in fifteen months. Having realized his inability to keep up with the payment schedule, he decided to clear the loan with one single payment in 17 months. If the interest rate on the loan is 5.85% p.a., what would be the value of this single payment? Use 17 months as the focal date