Quantitative Aptitude - Arithmetic Ability Questions

At 6′o clock a clock ticks 6 times. The time between first and last ticks is 30 seconds. How long does it tick at 12′o clock ?

Abhinav scores 80% in physics and 66% in chemistry and the maximum marks of both the papers are 100. what percent does he score in maths which is of 200 marks, if he scores 80% marks in all the three subjects: 

12 buckets of water fill a tank when the capacity of each tank is 13.5 liters. How many buckets will be needed to fill the same tank,if the capacity of each bucket is 9 liters?

Two numbers are 35% and 42% are less than a third number .How much percent is the second number less than the first ?

An equilateral triangle is described on the diagonal of a square. What is the ratio of the area of the triangle to that of the square?

Raju got married 8years ago. His present age is 6/5 times his age at the time of his marriage  Raju's sister was 10years younger to him at the time of his marriage. The present age of Raju's sister is  ?

A sum of money triples itself in 8 years simple interest. Find the rate of percent per annum?

In a village the average age of n people is 42 years. But after the verification it was found that the age of a person had been  considered 20 years less than the actual age, so the new average, after the correction,increased by 1. The value of n is :