A primary root grows from 5 cm to 19 cm in a week. Calculate the growth rate and relative growth rate over the period.


Lt = L0 + rt ... (i)

where Lt = length at time ‘t’ , L0 = length at time ‘zero’ , r = growth rate / elongation per unit time.


Here, Lt = 19 cm


L0 = 5 cm


t = 1 week


Putting these values in equation (i)



Relative growth rate =


=


Hence the growth rate is 14 cm per week while the relative growth rate is 280%.


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