Can someone help with this please.

Asequence has a common ratio of and f(5) = 81. which explicit formula represents the sequence? f(x) = 24 f(x) = 16 f(x) = 24 f(x) = 16

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!

I’m not sure about what the answer is