The easiest way to know which tree is growing fastest is to find the slope of each tree growth.
Slope of tree A is already given, and is 4
For the slope of tree B, use two of the pairs given on the table.
[tex]m=\frac{12-3}{2-0}=\frac{9}{2}=4.5[/tex]
Similar procedure is done for the slope of tree C, use two points on the graph to find the slope.
[tex]m=\frac{17-10}{2-0}=\frac{7}{2}=3.5[/tex]
The greatest slope is 4.5 and corresponds to tree B, it means tree B is the one that is growing fastest.
Tree A was 5 inches tall when first planted, tree B was 3 inches and tree C was 10 inches. It means the tallest tree when it was first planted as tree C.
After 6 months, tree A will be (4*6)+5=29 inches.
After 6 months tree B will be (4.5*6)+3=30 inches.
After 6 months tree C will be 31 inches.
It means that after 6 months, tree C will be the tallest of them.