Can you place three balls such that the equation shown in the picture holds true?

I am green and found in the forest and have needles instead of leaves. What am I?
Hint 1: It can be used for Christmas decorations.
Hint 2: I have a strong, scent that is used in air fresheners.

Eight of us go fourth, not back, to protect our king from an attack. What are we?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?