Quantitative Aptitude - Arithmetic Ability Questions

If a person walks at 15 km/hr instead of 9 km/hr, he would have walked 3 km more in the same time. What is the actual distance (in kms) travelled by him? 

What is the average of first 19 odd numbers?

If I walk at 7/6 of my usual speed, then I reach my office 15 minutes early. What is the usual time taken (in minutes) by me to reach the office?

Find the third proportional to 6 and 12.

A profit of Rs. 960 is divided between A and B in the ratio 1/3:1/2. The difference of their profit is :

Ravi sold a smartphone for Rs. 30,000. Had he offered a discount of 10% on the selling price(SP), he would have earned a profit of 35%. What is the cost price?

A cistern has one inlet, L and one inlet, M. L takes 5 hours to fill the empty tank, when M is not open and M takes 8 hours to empty the full tank, if the tank is two fifth full, how much time will it take to fill the tank completely when both L and M are opened simultaneously? (in hours)

A, B and C can do a job working alone in 12, 16 and 24 days respectively. In how many days they can do the job if they worked together?