Write and solve an inequality for each problem. 8. By selling old CDs, Sarah has a store credit for $153. A new CD costs $18. What are the possible numbers of new CDs Sarah can buy? 9. Ted needs an average of at least 70 on his three history tests. He has already scored 85 and 60 on two tests. What is the minimum grade Ted needs on his third test? 10. Jay can buy a stereo either online or at a local store. If he buys online, he gets a 15% discount, but has to pay a $12 shipping fee. At the local store, the stereo is not on sale, but there is no shipping fee. For what regular price is it cheaper for Jay to buy the stereo online?