Randall will have 4 sandwiches. If he wants 1 foot pieces and has 4 feet of sandwich, that will turn into 4 of them.
0.7(6)^-x = 0.7 * 1 /6^x)
the graphs would be a reflection of each other in the y axis
42/12 = 3.5, 63/18 = 3.5, therefore we will be multiplying the last time by 3.5. 40x3.5= 140, and therefore, the number of pencils produced in 40 seconds is 140