Can you find the mistake in the below statement?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

how come the second man dies?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Which five letter word can be added at the end of below word to form a
valid word?

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Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

Fate has decided that you will only be pleased to meet me when you need me

Maybe that is why, when I am working, I start working

However annoying I may be to the regulars, the little ones are always inspired

I will always be waiting if you try to reach me

How many of you can guess my name, let me see