The sum of the digits

If you think that mathematics and arithmetic is something for boys, you probably never read about Shakuntala Devi. Born in 1929, as a young child she was taken by her father on road shows to display her abilities for mental calculation. At the age of six she demonstrated her abilities at the University of Mysore.

In 1977, when she must have been 48, at Southern Methodist University, she gave the 23rd root of a 201-digit number in 50 seconds.[6][4] Her answer, which was 546,372,891, was confirmed by calculations done at the US Bureau of Standards by the UNIVAC 1101 computer, for which a special program had to be written to perform such a large calculation, which took a longer time than for her to do the same.

She wrote several books, on puzzles, astrology, memory and homosexuality. What interests us here is the book “Puzzles to puzzle you”.
Here is one of them:
Which number is exactly 3 times the sum of its digits?

In her honor :
Which number is exactly 11 times the sum of its digits?

You can check your solution here

The successor of the Sultan (1)

It was already known that the Sultan of Buhrundipur was a cruel men. It is only through recent research that we learnt how cruel. We already knew that the empire collapsed after his demise. He put all candidates whom he considered to be a possible successor through a series of tests, which have only now come to light.

Test 1^**/*****
There are 3 boxes, each with a label. One box holds a treasure, two boxes hold a deadly poison which is released when opening the box. One label tells the truth, the other two are lies.
Box 1: “This box holds a poison”
Box 2: “This box holds a treasure”
Box 3: “The label on box 2 is false”

Which box should the candidate open?

New puzzles are published at least once a month on Fridays. Solutions are published after one or more weeks. You are welcome to remark on the difficulty level of the puzzles, discuss alternate solutions, and so on. Puzzles are rated on a scale of 1 to 5 stars. You can check your solution here.