All you have to do is the amount she bought divided by 0.05 and then add the answer you get to the amount she bought each time
Answer:

Step-by-step explanation:

You have to prime factorise 81 and then you will get <u>9</u> as the answer.
Place it in front of the second digit hopefully that helps I'm sorry I'm really tired
2, No solution
3, Infinite many solutions
4, (0,-3)
i hope i was able to help!! so sorry if i made a mistake