Brain-Teaser 477

From The Sunday Times, 19th July 1970 [link]

His four wives have to make tribute of goats to the Khan of Bakristan. My job is to collect the goats.

“Kahn Sahib says each gift to be divisible by donor’s age which consists of first and third digits of her number of goats”, said Munshi. “I don’t know ages, but know the goats required from each”.

I knew their ages. To celebrate each wife’s 31st birthday the Khan had married a teenager, so I quickly jotted down the four numbers of goats — no names because Munshi was looking over my shoulder and reading each of my four numbers from right to left, as they do in Bakristan. “Numbers correct”, he said.

Having done things the opposite way my numbers agreed with his.

What are the ages of the 3rd and 4th wife?