A: We want to select one person who works out three days a week. Our probability is simply 12/80 ~~ 15%
B: At least 4 days a week means 4 days, 5 days, or 6 days.
Hence, we have: (9 + 20 + 8)/80 = 46%
C: At least once a week.
Let's find out how many DO NOT work out and subtract that from our sample space. This means they must work out at least once a week.
(80 - 15)/80 = 81%
9^3 x 8 is the answer I believe
Let the hamburgers be x and cheese burgers be y.
x + y = 24
3x + 3.5 y = 79
x = 24 - y.
Substituting the value of x,
3( 24 - y) + 3.5 y = 79
72- 3y + 3.5 y = 79
72 + 0.5 y = 79
0.5y = 79 - 72 = 7
1/2 y = 7
thus, y = 7 * 2 = 14
Substituting the value for x,
x + y = 24
x + 14 = 24
x = 24-14 = 10
Thus, x = 10.
Thus, she sold 10 hamburgers and 14 cheeseburgers
