Quantitative Aptitude - Arithmetic Ability Questions

A boy found the answer for the question "Subtract the sum of 1/4 and 1/5 from unity and express the answer in decimals" as 0.45. The percentage of error in his answer was

The point of intersection of all the three medians of a triangle is called its

A company, at the time of inflation reduced the staff in the ratio 5 : 3 and average salary per employee is increased in the ratio 7 : 8. By doing so, the company saved Rs 55000. What was the initial expenditure (in Rs) of company?

If a dairy mixes cow's milk which contains 10% fat with buffalo's milk which contains 20% fat, then the resulting mixture has fat (120/7)% of fat. What ratio was the cow's milk mixed with buffalo's milk?

Raghu goes to college at a speed of 4 kmph and returns at a speed of 3 kmph. If he takes 5.95 hrs in all, then what is the distance between his home and the college?

A can do a work in 21 days and B in 42 days. If they work on it together for 7 days, then what fraction of work is left?

In what ratio must a mixture of 20% milk strength be mixed with that of 60% milk strength so as to get a new mixture of 25% milk strength ?

A passenger train running at the speed of 80 kms/hr leaves the railway station 6 hours after a goods train leaves and overtakes it in 4 hours. What is the speed of the goods train?