What four weights can be used to balance from 1 to 30 pounds?

Find the next number in the series below

21 32 54 87 131 ?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

A pregnant woman is preparing to name her seventh child. Her children's names so far are Dominique, Regis, Michelle, Fawn, Sophie, and Lara. What will she name her next child -- Jessica, Katie, Abby or Tilly?

A small town is visited by an ice-cream truck every day. On the first day of February, the truck visits as usual and 5 children, one from each of the first 5 houses on the street buys an ice cream that is of the different flavor from each other along with a completely different topping.

Go through the details below and find out which child lives in which house and bought which ice-cream flavor with which topping:

1. Jim lives between the child who bought the Raspberry topping and the child who bought mango ice cream.

2. Joyce, whose house has an even number, bought the cherry topping. Nancy does not live next to Joyce.

3. The blackcurrant ice cream had no topping.

4. The child who lives in house number 2 had the butterscotch ice cream. The child in house number 3 did not have chocolate ice cream.

5. Mike had banana ice cream. He hates banana cherry.

6. The child who had the cashew topping lives in house number 5. Dustin does not live in house number 4.

Please note that the odd numbered houses and the even numbered houses are located on the exactly opposite sides of the street.

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

Replace the question mark with the correct number below.

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.

If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?