The height of the in inches after 30 day is 40.6 inches.
Explanation:
The initial height of the plant = 7 inches
The increase in height for first 27 days = 1.3 inches per day
So, increase in height in 27 days = 27 x ( per day increase) = (27 x 1.2) in
Now, the total length of plant after 27 days
= Initial height + ( increase in height in 27 days)
= 7 inches + (1.3 x 27) in = 7 + 35.1
= 42.1 inches
So, at the end of 27 days, the height of plant = 42.1 inches
Now, the decrease in height for each 3 next days = 0.5 inches per day
So, decrease in height in 3 days = 3 x ( per day decrease) = (0.5 x 3) in
⇒The total length of plant after 30 days
= The height after 27 days - ( decrease in height in 3 days)
= 42. 1 inches - (0.5 x 3) in = 42.1 - 1.5
= 40.6 inches
Hence, the height of the in inches after 30 day is 40.6 inches.