Please help. I don't understand how im suppose to apply the doubled amount. And if its 10 years ago, would the amount be -20? I belive the equation is A(t)=Ae^rt but im not sure

The first week samantha learned to read braille, she could read 10 words per minute. in the second week she increased her speed by 20%. in the third week she increased her speed again by another 25%. how many words could she read per minute by the third week? hurry and tell me!