Question

For an experiment in Botany, two different plants, plant A and plant B were grown under similar laboratory conditions. Their heights were measured at the end of each week for 3 weeks. The results are shown by the following graph.

1. How high was Plant A after (i) 2 weeks (ii) 3weeks?
2. How high was Plant B after (i) 2 weeks (ii) 3weeks?
3. How much did Plant A grow during the 3rd week?
4. How much did Plant B grow from the end of the 2nd week to the end of the 3rd week?
5. During which week did Plant A grow most?
6. During which week did Plant B grow least?
7. Were the two plants of the same height during any week shown here? Specify.

Answer 1

(a)
(i) After $2$ weeks, the height of plant A was $7$ $cm$.
(ii) After $3$ weeks, the height of plant A was $9$ $cm$.

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(b)
(i) After $2$ weeks, the height of plant B was $7$ cm.
(ii) After $3$ weeks, the height of plant B was $10$ cm.

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(c) Growth of plant A during 3rd week = $9 \;cm - 7\; cm$ = $2$ $cm$

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(d) Growth of plant B from the end of the $2$nd week to the end of the $3$rd week
= $10 \;cm - 7 \;cm = 3 \;cm$

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(e) Growth of plant $A$ during $1$st week = $2\; cm - 0 \;cm = 2 \;cm$
Growth of plant $A$ during $2$nd week = $7\; cm - 2 \;cm = 5\; cm$
Growth of plant $A$ during $3$rd week = $9 \;cm - 7 \;cm = 2 \;cm$
Therefore, plant $A$ grew the most, i.e. $5$ $cm$, during the $2$nd week.

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(f) Growth of plant $B$ during $1$st week = $1 \;cm - 0 \;cm = 1 \;cm$
Growth of plant $B$ during $2$nd week = $7 \;cm - 1 \;cm = 6 \;cm$
Growth of plant $B$ during $3$rd week = $10 \;cm - 7\; cm = 3 \;cm$
Therefore, plant $B$ grew the least, i.e. $1$ $cm$, during the $1$st week.

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(g) At the end of the 2nd week, the heights of both plants were same.