One thousand and twenty students participated in the school math contest. Sample 1 is a random sample from grades 9 and 10 and consists of the following scores: 72, 89, 67, 81, 75, 79, 81, 80, 62, 64, 83. Sample 2 is a random sample from grades 11 and 12 and consists of the following scores: 84, 86, 87, 84, 86, 89, 90, 87, 87, 84, 86.

graph b

step-by-step explanation:

one solution- graph a (clear intercepting point.)

no solution- graph b (they're parallel, there will never be a point of interception.)

infinite solutions- graph c (all points intercept.)

step-by-step explanation:

given that ab is divided into equal parts as

ac, cd, de, ef, fg, gh, hi, ib.

from this we find that f is the midpoint of ab.

so using mid point formula we find

f = (3,7)

similarly considering fb, we get

h = mid point of fb = ((6,6) and g, mid point of fh is

g = (9/2, 13/2)

i is mid point of hb

so i =(15/2,11/2)