An environmental initiative requires a company to make monthly carbon-offset payments. The payment in the first month is P1=£4,250P_1 = £4,250P1=£4,250, and the payment in the second month is P2=£5,375P_2 = £5,375P2=£5,375. The monthly payments PnP_nPn follow an arithmetic progression. The final payment made is £54,875£54,875£54,875.
Find
the total number of months for which the company made payments,
the total sum of all carbon-offset payments made over the duration of the initiative.
