Question

For an experiment in Botany two different plants, plant A and plant B were grown under similar laboratory conditions. The heights were measured at the end of each week for $3$ weeks. The results are shown by the following graph.
(a) How high was Plant A after (i) $2$ weeks (ii) $3$ weeks?
(b) How high was Plant B after (i) $2$ weeks (ii) $3$ weeks?
(c) How much did Plant A grow during the $3^{rd}$ week?
(d) How much did Plant B grow from the end of the $2nd$ week to the end of the $3rd$ week?
(e) During which week did plant A grow most?
(f) During which week did plant B grow least?
(g) Were the two plants of the same height during any week shown here? Specify.

Answer 1

In the graph $x-$axis represents weeks and $y-$axis represents the heights of the plant.

Scale :

On $x-$axis $7$ cm $=1$ week

On $y-$axis $1$ cm $=1$ cm in height

To find the height of plant at particular week:

Trace the vertical line parallel to $y-$axis passing from the point on $x-$axis, find the point where this vertical line intersects the graph.

Now from that point trace a horizontal line parallel to $x-$axis, this line intersects the $y-$axis at required point.

To find the week at particular height:

Trace the horizontal line parallel to $x-$axis passing from the height point on y-axis, find the point where this horizontal line intersects the graph.

Now from that point trace a vertical line parallel to $y-$axis, this line intersects the $x-$axis at required point.

Now,

a) Follow step 1 on graph for plant A at point i) $2$ weeks and ii) $3$ weeks, we get corresponding heights on $y-$ axis, $7$ cm for $2$ weeks and $9$ cm for $3$ weeks.

b) Follow step 1 on graph for plant B at point i) $2$ weeks and ii) $3$ weeks, we get corresponding heights on $y-$ axis, $7$ cm for $2$ weeks and $10$ cm for $3$ weeks.

c) To find grow during $3^{rd}$ week, we have to find the height difference between $2^{nd}$ and $3^{rd}$ week, which is $9$ cm $-7$ cm $=2$ cm

d) To find grow of plant B from end of $2^{nd}$ week to end of $3^{rd}$ week, we have to find height difference between $3^{rd}$ and $2^{nd}$ week, $10$ cm $-7$ cm $=3$ cm

e) Find the grow of height level of plant A weekwise

$1^{st}$ week: $1$ cm $-0$ cm $=1$ cm

$2^{nd}$ week: $7$ cm $-1$ cm $=6$ cm

$3^{rd}$ week: $9$ cm $-7$ cm $=2$ cm

so plant A grows on $2^{nd}$ week the most

f) Find the grow of plant B week-wise

$1^{st}$ week: $2$ cm $-0$ cm $=2$ cm

$2^{nd}$ week: $7$ cm $-2$ cm $=5$ cm

$3^{rd}$ week: $10$ cm $-7$ cm $=3$ cm

so plant B grow least on week $1^{st}$

g) Graphs of plant A and plant B intersects at ($2^{nd}$ week and $7$ cm height), so plants were in same height which is $7$ cm.