Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.
How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

John is pretty weird. He likes toffees but hates chocolates. He loves books but never reads. He likes to build his troops in an online game but does not proceed with the war. He likes to go swimming but is afraid of water.

Seeking this behaviour, can you tell whether he likes balloons and parties?

What's the best place to go shopping in the ocean?

What does this Rebus Picture means ?

John was a very careless driver, so his owner Jacob gave him an offer that he will get an incentive of Rs.30 for every bottle box he delivered without breaking it and he will be charged Rs.90 for every bottle box he broke. Jacob gave John 100 bottles-box to deliver. After delivery, Jacob paid John Rs.2400. How many bottles-box did John break?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?