What is the next number in the series?

15 29 56 108 208 ?

Find the next number in the series below

21 32 54 87 131 ?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Three people are in a room. Ronni looks at the Nile. The Nile looks at Senthil. Ronni is married but Senthil is not married. At any point, is a married person looking at an unmarried person? Yes, No or Cannot be determined.

On my way to St. Ives I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kittens, cats, sacks, wives. How many were going to St. Ives?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

There are three Athletes (John, Tarun and Harish) and their individual Coaches (Jacob, Meenaxi and Priyanka) standing on the shore.
No Coach trusts their Athlete to be near any other Coach unless they are also with them.
There is a boat that can hold a maximum of two persons.
How can the six people get across the river?

Can you solve the below tricky visual equation?

There is a wide field of corn. A goose finds its way into the field and starts running. Can you find out till which point the goose can run into the field?

If 1+9+8=1, what is 2+8+9?