Quantitative Aptitude - Arithmetic Ability Questions

If a * b = 2a - 3b + ab, then 3 * 5 + 5 * 3  is equal to : 

A man walking at the rate of 5 km/hr crosses a bridge in 15 minutes. The length of the bridge (in metres) is

A contractor undertakes to do a piece of work in 40 days. He engages 100 men at the begining and 100 more  after 35 days and completes the work in stipulated time. If he had not  engaged  the additional men, how many days  behind schedule would it be finished?

What will be the average of the first 7 positive odd numbers divisible by 5?

The ratio of selling price to the cost price is 21 : 16. What is the profit percentage?

The length and breadth of a rectangle are 21 cm and 20 cm respectively. Find its area (in cm2).

In the following question, select the related number from the given alternatives.

8 : 27 : : 64 : ?

A Shopkeeper sells two articles at Rs.1000 each, making a profit of 20% on the first article and a loss of 20% on the second article. Find the net Profit or loss that he makes?