Inside a square ABCD, triangle BEC is an equilateral triangle. If CE and BD intersect at O, then ∠BOC is equal to?

In each of the following questions, four words have been given, out of which three are alike in some manner and the fourth on is different. Choose out the odd one.

Identify the segment in the sentence which contains the grammatical error.

Two American cities, witnessed shooting and resulting in mass fatalities over the weekend.

A number in the given number series is incorrect. Find the wrong number.
120, 143, 168, 196, 224

Statement: 

All insects are dangerous. 

All machines are dangerous. 

Conclusion 

I. All dangerous are insects. 

II. All dangerous are machines. 

III. Some machines are insects. 

Directions : What should come in place of the question mark (?) in the following number series? 

55 109 ? 433 865 1729 

In which group can you find or replace text and select text or objects in a document?  

Scitech Airon Technology has been adopted by which state?