Answer:
David is saving up money to buy a new car. He had $1,350 saved up 4 months ago, and now has $2,150. He adds the same amount of money each month
Explanation:
I'm not clear on your actual question, but I'm guessing you want to know how much money he has saved each of the last four months.
2150 - 1350 = $800 saved over the past four months
$800 / 4 months = $200 saved per month