Here's the question you clicked on:
sarmandi
a 80 cm tall sunflower increases its length by 5% per day during a sunny period. a) how much growing sunflower in a week?
there is a method of successive % change which can be applied here. But you will have to apply it 4 times as it is only valid for 2 quantities. \[a +b +\frac{ ab }{ 100 }\] Where a and b are percentages.
The Better way is that you follow @satellite73, @sarmandi His method is easy and quick.