SimaQ wrote:

II question....

We know the two lenghts of the triangular is 5 and 2.

The key here is to keep in mind that the sum of any two sides of the triangular cannot be less than the length of the remaining side....

to be explicit, let a, b and c be the three sides

Assign a, b to the two known sides.

c must satisfy the condition that is:

|a-b| < c< a+b

(| | is used here because we don't know if a> b or vice versa)

Apply this rule, the third side must be in the range from 3 to 7 exclusively

so the perimeter must be from 10 to 14

None of the choices satisfies.