Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

In the image below, can you find the value of an angle(y)

Find the next number in the series below

21 32 54 87 131 ?

What has many keys but can’t open a single lock?

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?

Solve the following series:
AZ, GT, MN, __, YB