During a shopping spree in China $,$ C$.$ Dundee has bought a Sony CD boom box $($with woofers and tweeters$)$ for CY $2,000,$ jade jewelry for CY $4,000,$ and four custom$-$made suits for CY $25,000.$ The spot exchange rate is CY$/$AUD$=5.$

$($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 HKD $10,000$ paid for airfare and hotels during his trip?