Read the following question and decide which of the given statements is/are sufficient.
In a class of 50 students, how many girls scored above 80% in Maths?
Statements:
1. Exactly four boys scored above 80% in Maths.
2. One-third of the class scored above 80% in Maths.

correct answer should be :

Both 1 and 2 together are sufficient to answer the question.

In a class of 50 students
Statements I
1. Exactly four boys scored above 80% in Maths.

it means that 46 students scored less that 80%. from this statement we can conclude any colusion

2. One-third of the class scored above 80% in Maths.

     One-third of 50 = 16.33 which means 16 students scored above 80% in Maths. from this statement we can conclude

but by combining both

16 students including 4 boys scored above 80% in Maths.

so 12 girls scored above 80% in Maths.