286. you just subtract the two numbers
I don't know, this is tricky
Well, first you would have to draw the three pizzas, then spilt them all in half, so each friend would have a half of pizza! Hope this helped!
His first payment is $100, thus a₁ = 100.
the next "term", month will be 1.1 times more than the one before, namely r = 1.1, the common ratio.


is the serie divergent or convergent?
well, to make it short, when the common ratio is 0 < | r | < 1, namely a fraction between 0 and 1, only then the serie is convergent, namely it reaches a fixed value, now in this case, 1.1 is a value larger than anything between 0 and 1, so no dice.