Joe ate 7/30 more of pizza than Jane. You can just subtract 2 uneven denominators. So you would turn them into 30 because that’s the closest highest number that can go with 5 and 6. Then multiply 2 with 6 which is 12 and then multiply 1 with 5 which is 5 now you can subtract it. 12/30-5/30=7/30.
So.. in this case, the starting amount is the 500mg sample... and the rate of decay, negative rate, is 1%, and at the time, the elapsed days is 0, to t = 0, P = 400
