I need help pls how do u do this step by step? ):

Ok so this is how you do it: you do it by answering the question so the elephant needs water to drink 20 percent of the earth

I would say A is better. If the stock is up by 30% but then drops by 20%. Your Stil up by 10%.
However with b, if your stock drops by 25% then goes up by 35% overall you only have a +5%.
A.
Hope this helps :)

20y5 times 2 is 1010 times -2 is -20, plus y