Question 382401
Okay, let;s start with a,

let c equal cost, let l equal pounds

C=1.09l

Now, b,
1.09*4.5=4.905

So, it will cost $4.91, because we have to round up.

Finally, c,

1.09*9.2= 10.028

That's about 10 dollars

20-10=10

You will get 10 dollars change