Here is an easy puzzle:
Take a break and solve this puzzle..
A king asks a learned man to visit his palace. The man says I will come any day next month. But give me gold in gms equal to the date on which I come. The king asks the jeweler to make rings of 1 to 31 gms. The jeweler was smart and makes only 5 rings. What was the weights of those rings?

Respuesta :

the answer is 
date
1                  2                 3          4             5                                         31
r1                r2               r3           r4          r5               .  .  .                  r31
1gm           2gms         3gms     4gms    5gms        .   .  .                 31gms

r1+r2+ .... +r31= 31(31+1) /2=496gms  (31 rings)

he only made 5 rings

31 rings----------> 496 gms
5 rings ------------> ? = 5 x496  / 31=80 gms

 the weights of those 5 rings was 80 gms