Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

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 many Watermelons are there in the below picture?

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

If a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

Identify The phrase in the picture.

I add 5 to 9 and get 2. The answer is correct, so what am I?