"Silver jubilee" joke

Banta and Preeto decided to celebrate their 25th Wedding Anniversary with a trip to Mumbai. When they entered the hotel and registered, a sweet young woman dressed in a very short skirt became very friendly. Banta brushed her off."
Preeto objected, "That young woman was nice, and you were so rude."
"Preeto, she's a prostitute."
"I don't believe you. That sweet young thing?"
"Let's go up to our room and I'll prove it."
In their room, Banta called down to the desk and asked for that girl to come to room 326.
"Now," he said, "you hide in the bathroom with the door open just enough to hear us, OK?"
Soon, there was a knock on the door. Banta opened it and girl walked in, swirling her hips provocatively.
Banta asked, "How much do you charge?"
"Ten thousand basic rate, three thousand tips for special services."
Even Banta was taken aback. "Ten thousand !! I was thinking more in the range of two thousand." Girl laughed derisively. "You must really be a hick if you think you can buy sex for that price."
"Well," said Banta, "I guess we can't do business. Goodbye."
After she left, Preeto came out of the bathroom. She said, "I just can't believe it!"
Banta said, "Let's forget it. We'll go have a drink, then eat dinner."
At the bar, as they sipped their cocktails, that girl came up behind Banta, pointed slyly at Preeto, and said, "See what you get for rupees two thousand !"