Correct Answer:  Man 2 will shout out after some time.

Explanation:

Here’s why: Man 3 and 4 cannot see the other hats.
Man 1 sees a white hat and a black hat and knows his hat can be black or white.
Man 2 sees one black hat , but if he is also wearing a black hat, it would be obvious to Man 1 that he is wearing a white hat. Since Man 1 did not shout out, Man 2 concluded that he himself is wearing a white hat.

Ans credits: RedTaurus

Correct answer : 8

Method-1
√9+√64=11
√4+√25=7
√1+√49= 8?

Method-2
Addition of two larger numbers minus the smaller number
(9+6)-4=11
(4+5)-2= 7
(4+9)-1= 12?

The answer to this “Missing Number in Last Triangle Puzzle“, can be explained with smart solution. Addition of two larger numbers minus the smaller number of the Triangle.