Question

Morgans plant grew from $42$ centimeters to $57$ centimeters in a year. Lindas plant, which was $59$ centimeters at the beginning of the year, grew twice as many centimeters as Morgans plant did during the same year. How tall, in centimeters, was Lindas plant at the end of the year?

• A. $88$
• B. $89$
• C. $90$
• D. $91$

Answer 1

Answer: (B)

$89$

Given

Initial length of Morgans plant $=$ $42$ $cm$

Final length of Morgans plant after an year $=$ $57$ $cm$

Increase in length of Morgans plant in that year $=$ (Final length $-$ Initial length) of the Morgans plant

$=$ $57$ $cm$ $-$ $42$ $cm$

$=$ $15$ $cm$

Therefore, Increase in length in Morgans plant is ${}^{\prime }{15}^{\prime }$ $cm$.

Now given, lindas plant grew twice as many centimeters as Morgans plant.

Increase in length of Lindas plant $=$ $2$ $\times$ Increase in length of Morgans plant

$=$ $2$ $\times$ $15$ $cm$

$=$ $30$ $cm$

Therefore, Increase in length of Lindas plant is ${}^{\prime }{30}^{\prime }$ $cm$.

Initial length of Lindas plant $=$ $59$ $cm$

Final length of Lindas plant $=$ (Initial length $+$ Increase in length) of Lindas plant

$=$ $59$ $cm$ $+$ $30$ $cm$

$=$ $89$ $cm$

Therefore, Lindas plant is ${}^{\prime }{89}^{\prime }$ $cm$ tall at the end of the year.