ur looking for the scale factor....and it is the number that u multiply the first image by to get to the second image
so 5 times what = 1
5x = 1
x = 1/5 (or 0.2)
so the scale factor is 1/5 because 5 * 1/5 = 1
so ur answer is : 1/5 , which in decimal form is 0.2<==