1.To settle the purchase of a house, Aimar has to pay a down payment of $10000 plus $2000 at the end of the first month, $1900 at the end of the second month and $1800 at the end of the third month and so on for 20 months. Calculate the total payment.

2. Haiden has to pay $10 at the end of the first month, $30 at the end of the second month, $90 at the end of the third month and so on for seven months. Calculate the total amount he has to pay.