A. They are both proportional because they have the same ratio. b. The two graphs are the same because they have a constant rate of change (50), but they have different y-intercepts.
We would have to multiply the original amount by 1.50^x because the initial amount would be 1, and 50% increase would be .5 so 1.5 and you raise it to the number of years to show the total increase.
