Solution:

A coconut.

Explanation:
Thirsty: she can drink coconut water.
Hungry she can eat coconut's malai.
Cold: she can burn the cover of the coconut.

Solution:

The man said, 'I will be killed by giving poison.'

If Akbar says the statement is true, the man will be killed by hanging which will make his statement false.
If Akbar says the statement is false, the man will be killed by giving poison which will make the statement true.

Thus Akbar had no choice but to leave the man unpunished.

Solution:

Birbal wrote - "This time will pass soon."

When read in good time, you will feel sad. However, it is essential to keep the fact in the mind. Thus, do not be haughty and keep doing the good work for society.

When read in bad time, you will feel optimistic and get a morale boost that with your hard work you can change the situation.

Solution:

This is what Birbal said after bowing in front of the real king:
"Your majesty, the other kings were watching you closely in order to imitate you accurately while you were sitting with your calm and composed demeanor. This is how I found out that you are the real king."

His Quick wit flabbergasted the king and he was rewarded with luxurious gifts and jewels in return.

Solution:

25 Fruits

Remember we told you that Birbal is a witty trader. So his sole motive is to get rid of the sacks as fast as he can.

For the first sack:
He must be able to fill fruits from one sack to other two sacks. Assume that he is able to do that after M check points. Now to find M,

(Space in first sack) M + (Space in second sack) M = (Remaining fruits in Third Sack) 30 – M
M = 10

Thus after 10 checkpoints, Birbal will be left with only 2 sacks containing 30 fruits each.

Now he must get rid of the second sack.
For that, he must fill the fruits from second sack to the first sack. Assume that he manages to do that after N checkpoints.

(Space in First Sack) N = (Remaining fruits in second sack) 30 – N
N = 15

Thus after he has crossed 25 checkpoints, he will be left be one sack with 30 fruits in it. He has to pass five more checkpoints where he will have to give five fruits and he will be left with twenty five fruits once he has crossed all thirty check points.

Solution:

I will be thrown at lions. Now if Akbar threw him at lions, Birbal’s statement will stand true and he will have to bury him alive. But if he bury him, the statement will emerge as false. Thus he had no choice left

Solution:

Birbal drew another line that was larger than the pre-drawn line. Now the pre drawn line was smaller.

Solution:

Didn't you say that you sold your well to this farmer?' Birbal asked the neighbour. 'So, the well belongs to him now, but you have kept your water in his well. Is that right? Well, in that case you will have to pay him a rent or take your water out at once.'The neighbour realized that he was outwitted. He quickly apologized and gave up his claim."

Solution:

"Hold up one of your shields and I will pierce it with one of your spears," said Birbal with a smile.

Solution:

'Didn't you say that you sold your well to this farmer?' Birbal asked the neighbour. 'So, the well belongs to him now, but you have kept your water in his well. Is that right? Well, in that case you will have to pay him a rent or take your water out at once.'
The neighbour realized that he was outwitted. He quickly apologised and gave up his claim.