Quantitative Aptitude - Arithmetic Ability Questions

Find the fourth proportional to 2, 3, 6.

A student multiplied a number by 6/13 instead of 13/6. What is the percentage error in the calculation?

Karan purchased one dozen pens for Rs. 120 and sold a pack of 3 pens for Rs.35 each. What is his gain?

Train A takes 1 hour more than train B to travel a distance of 720 km. Due to engine trouble speed of train B falls by a third, so it takes 3 hours more than Train A to complete the same journey? What is the speed of Train A (in km/hr)?

Two taps X and Y can fill a tank in 15 hours and 20 hours respectively. If the two taps are opened at 2 p.m., then at what time (in p.m.) should the tap X be closed to completely fill the tank at exactly 2 a.m.?

The difference of squares of two numbers is 180. The square of the smaller number is 8 times the larger number. Find two numbers.

In a computer game, a builder can build a wall in ten hours while a destroyer can demolish such a wall completely in fourteen hours. Both, the builder and the destroyer were initially set to work together on level ground. But after 7 hours the destroyer was taken out. What was the total time (in hrs) taken to build the wall ?

A trader allowed a discount of 15% on a trolley bag having list price of Rs 1360 and earns a profit of 15.6%. What is the cost price (in Rs) of the trolley bag?