Aryan invested ₹ 5200 at 4 %, 6 % and 8 % per annum simple interest. At the end of the year, he got the same interest in all the three cases, find the money invested at 4%. 

A class has 90 students, of which 60 percent are girls and the rest are boys. Boys' average score in English is 30 percent higher than girls. If the average score of all students in English is 56, then what is the average score of only girls in English?

A number increased by   $$22{1 \over 2}\%$$ gives 98 as result. The number is: 

What should come in place of the question mark (?) in the following question?
24% of 420 × 50% of 74 = ?

A train travelling at the speed of 50 kmph leaves from a station. Another train travelling at speed of 60 kmph leaves the same station after 7 hours in the same direction. They will meet after what distance?

In how many different ways can the letters of the word 'NATIONAL' be arranged?

The average of the marks obtained in an examination by 8 students was 51 and by 9 other students was 68. The average marks of all 17 students was: