What is a 4 digit number divisble by both 5 and 6

30

5*6=30

6*5=30

If n is divisible by 5 and by 6, then it is divisible by 30, and conversely; so just apply your method with d=30

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50

i think that you should ask google for the answer to that problem because if we don't know it google does