Answer :
Since each month profit is $1,900, it should be multiplied by 1900 as the time goes by. For example, one month profit is 1900, two month profits are 2*1900, three months profits are 3*1900, and so on...
So, it's Y (the amount of profits after X months) = 1900*X
So, it's Y (the amount of profits after X months) = 1900*X