You buy a car, and wish to pay the car seller $12,000, divided into 24 payments, so that each payment is $20 m?

The second month you pay $20 more, next $40 more ........ up to the 24 th payment you pay 23 x $20 more or $460 more.

adding these extra increments 20 +40+ 60+80............460 = 5520

(NB 5520 = (11 x480) +240 this is the quick way to add these numbers - 1st and last 20 + 460 = 480, 2nd and 2nd last 40 + 440 = 480 , 3rd and 3rd last = 60+420 = 480 and so on for 11 pairs. Then don't forget to add the midpoint 12 th increment of 12x 20 = 240.)

Subtract the total of the additional increments from the total cost,

12000 - 5520 = 6480

Divide by 24 = $270

The first instalment is $270

buy car pay car seller 12000 divided 24 payments payment 20

Your initial payment is x. Each month your adding 20 to x. So x + (x+20) + (x+40) etc is going to equal 12000.

You should be able to figure it out from the above. I'll even give you a hint, I came up with a number between 200 and 300.