15=-4+z/3
+4 +15 = +4 -4 +z/3
cancels the 4 on the right side
19 = z/3
3 x 19 = z/3 x 3
cancels 3 on the right side
I think the answer is z = 57
The old mean was 51 now the mean is 42.33... (round that to 42) 51 - 42 = 9
I think that the number of times you drink all the water in your bottle is independent, because the number of liters you drink depends on how much there is.
Independent- the number of times you drink all the water in your bottle
Dependent- the number of liters you drink
B. Is the correct answer. For part B, he can buy 15 balloons since X=15. Plug this back into the equation to check: 2(15)+20=50.
2(15)=30+20=50.