How many words can a pen with half refill write?

In a family supper, a grandfather, a grandmother, two fathers, two mothers, four children, three grandchildren, one brother, two sisters, two sons, two daughters, one daughter-in-law, and one mother-in-law need to sit at a table.

There are only seven chairs available at the place. How many more chairs do they have to borrow so that everyone can sit down together for the suppers if everybody requires a separate chair?

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?

If eleven plus two equals one, what does nine plus five equal?

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?

No matter how little or how much you use me, you change me every month. What am I?

What has no start, end, or centre?

Can you solve the photo plexer logic ?

Can you find out the number that should replace the question mark with a valid reason?

At my favorite fruit stand,
an orange costs 18,
a pineapple costs 27,
and a grape costs 15.
Using the same logic, can you tell how much a mango costs?