What is in seasons, seconds, centuries and minutes but not in decades, years or days?

I am an eight letter word and I am a computer terminology.
The second, third and fourth letters make an animal.
The fourth, fifth, sixth, seventh and eighth letters make a weapon.
The first, second, third and fourth letters can be taken as an outcome of any exam.
The fifth, sixth, seventh and eighth letter combine to form a high end typing software.

Can you tell who am I ?

Can you solve the below algebraic mathematical equation?

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

I have Rs.50 and I spend it in the way as below.

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

How can you make number one disappear by adding something to it?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

Replace the question mark with the correct number below.

Find the value of "?" in the ball picture Riddle below:

Can you make a six-letter word using the letters N, A and B ?