Answer:
378.5 or just 378
Step-by-step explanation:
This is a linear model with x representing the number of generations that's gone by, y is the number of butterflies after x number of generations has gone by, and the 350 represents the number of butterflies initially (before any time has gone by. When x = 0, y = 350 so that's the y-intercept of our equation.)
The form for a linear equation is y = mx + b, where m is the rate of change and b is the y-intercept, the initial amount when x = 0.
Our rate of change is 1.5 and the initial amount of butterflies is 350, so filling in the equation we get a model of y = 1.5x + 350.
If we want y when x = 19, plug 19 in for x and solve for y:
y = 1.5(19) + 350
y = 378.5
Since we can't have .5 of a butterfly we will round down to 378
