ElectricPavlov

12/320 = .0375   0r  3.75%    have defects      3.75% x 560 = .0375x560 = 21 will have defects out of 560

SIMPLE interest =  14500 (.04) x 5 = 2900.

COMPOUNDED ANNUALLY   =  14500(1.04)^5 - 14500 = 3141.47

Let 'x' be the SMALLER number     the other number = x+37

the two added together = -103

x + (x+37) = -103

2x + 37 = -103

2x = -140

x= -70   (the smaller number)     the other number is  x + 37 =  -70 + 37 = -33 

Really cannot answer this question without the UNITS of the grain of sand   10^-3  What?  Milligrams? Grams? Kilograms?

That would be  C

Obviously, I did the 'iteration and interpolation' in my head.....but is there any way to solve it mathematically ?

First , let's put it into y=mx+b   form  'b' will be the y intercept    'm' is the slope

y-3=5(x-2)

y= 5x -7        y-intercept is -7

Hmmmm     I know the answer is x=4    but I am drawing a blank on how to get there !    Anyone else?

x=wt of small box     y = large box wt

First delivery 

    5x  + 2y = 96      solve for y = (96-5x)/2

Second Delivery

   8y + 3x = 163       Substitute for y

   8 ( ( 96-5x)/2 ) + 3x = 163       and solve for x

    384 - 20x +3x = 163

17x=221

x=13   =   small box wt   kg               y= (96-5x)/2 = large box wt = 15.5 kg