If the average marks obtained by Balu, Benjamin and Babur is 80 and the average marks of Benjamin and Babur is 83, find marks obtained by Balu.

The ratio of the speeds of the two airplanes is 11: 18. If the first airplane covers a distance of 1650 km in 3 hours, then what is the speed (m / s) of the second airplane?

Selling price of an article is $${7\over6}$$ of cost price. What is the profit percentage?

Ratio of age of father, mother and son is 9:8:3. Five years hence sum of their age will be 95 years. Find the age of son 5 years ago.

What will be the total number of pieces if the length of $$ {5}{1\over4}$$  the rib is cut to 3/4 m length?

In a class, the average score of girls in an examination is 73 and that of boys is 71. The average score for the whole class is 71.8. Find the percentage of girls. 

The marked price of a shirt and trousers are in the ratio 1 : 2. The shopkeeper gives 40 % discount on the shirt. If the total discount on the shirt and trousers is 30 %, the discount offered on the trousers is 

The total marks obtained by Abhishek in Zoology, Botany and Chemistry together is 180 more than the marks obtained by him is botany. What are the average marks obtained by him is zoology and Chemistry together?