15,17,19 are all odd numbers and add to 51
1.2 meters = 120 centimeters
amount of increase = 120-80 = 40 centimeters
40 ÷ 80 = 0.5 = 50%
There was a 50% increase.
You have to convert the 30 inches into you know what and add them all together
18. It would be the second graph. The third graph is eliminated as the boy takes a time period to shave, which means there should be a constant point (horizontal line) right after the first incline. The first one is eliminated as the boy takes a bath which requires another constant point in the graph.
19.
C
E
D
A
B
[-½, ¾]; use either "Substitution" or "Elimination" to do this, and you'll see that this answer is correct.