What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

15 caves are arranged in a circle at the temple of doom. One of these caves has the treasure of gems and wealth. Each day the treasure keepers can move the treasure to an adjacent cave or can keep it in the same cave. Every day two treasure seekers visit the place and have enough time to enter any two caves of their choice.

How do the treasure seekers ensure that they find the treasure in the minimum number of possible days?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

Why is it very easy to weigh a fish?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Find the next number in the series below

21 32 54 87 131 ?

A man was just doing his job when his suit was torn. Why did he die three minutes later?

A Shopkeeper sold a few chickens to four different customers on a particular day. It was such that each customer purchased half of the remaining chickens and half the chicken more.

Can you find out how many chicken were sold by the shopkeeper on that day if we tell you that the fourth customer bought a single chicken ?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?