I'm stuck on number 6! !

toby invested £7500 for 2 years in a saving account. he was paid 4% per annum compound interest. how much money did toby have in his savings account at the end of 2 years?

Find the solution of each of the following.

I’m confused on how to work the pie charts

You’re ordering more thread for blue jeans co. you usually purchase from ted’s threads, which sells 12 thread spools for $27. you recently received a notice from wade's wares that says you can buy thread from them for $2.30 each for the first 2 dozen and $2 a spool thereafter. you need to order 5 dozen spools. what percentage can you save by going with wade’s wares?