Quantitative Aptitude - Arithmetic Ability Questions

In a mixture, ink and water are in the ratio of 8 : 5. If 24 litres of water is added to the mixture, then the new ratio becomes 8 : 11. What is the total quantity (in litres) of water in the new mixture?

If X=32, then the value of 27x3-54x2+36x-11 is

If a merchant offers a discount of 25% on the list price, then he makes a loss of 5%. What % profit or % loss will he make if he sells at a discount of 10% of the list price?

What is the average of all natural numbers from 21 to 39?

If a+b-62+a2b2+1+2b=2ab+2a, then the value of a is 

Two trains start from a certain place on two parallel tracks in the same direction. The speed of the trains are 45 Km/hr and 40 Km/hr respectively. The distance between the two trains after 45 minutes will be

The value of ds+t÷ds÷dt

A book is sold at three successive discounts of 20%, 20% and 10%. What is the net discount (in percentage)?