During a shopping spree in China $,$ C$.$ Dundee has bought a Sony CD boom box $($with woofers and tweeters$)$ for $CY2,000,$ jade jewelry for $CY4,000,$ and four custom$-$made suits for $CY25,000.$ The spot exchange rate is $C\frac{Y}{A}UD=5.$

$($a$)$ If PPP held, what should the same boom box, jewelry, and suits cost in Australia?

$($b$)$ Suppose Mr Dundee is $($unexpectedly$)$ stopped at customs as he arrives in Melbourne, and must pay import duties of $20$percent. If the same boom box, jewelry, and suits cost AUD $450,$ AUD $1,500,$ and AUD $8,000$ in Australia respectively, was his shopping spree worth at least the CY$10,000$ paid for airfare and hotels during his trip?