Quantitative Aptitude - Arithmetic Ability Questions

Total 100 members are writing exam. In that 48 members are writing first exam, 45 members are writing second exam and 38 members are writing third exam. 5 members are writing all the three exams. How many members are writing 2 exams ?

Sharan and Mayukh, working together, can complete a task in 18 days. However, Mayukh works alone and leaves after completing 1/3 of the task. Then, Sharan takes over and completees the remaining work by himself. As a result, the duo could complete the task in 40 days. How many days would Sharan alone have taken to do the job if Mayuk' had worked faster than Sharan ?

A 200 m long train passes a motorcycler, running in the same direction at 12 km/hr, in 15 second and a jeep travelling in the same direction in 20 s. At what speed is the car travelling (length of both the motorcycler and jeep is negligible)?

Rishi bought 30 kg of sugar at the rate of Rs. 9 per kg and 45 kg of sugar at the rate of Rs. 10 per kg. He mixed both type of sugar and sold the mixture at the rate of Rs. 9.75 per kg. What was his gain or loss in the selling of whole sugar?

In an examination, a student scores 4 marks for every correct answer and loses I mark for every wrong answer. If he attempts in all 60 questions and secures 130 marks, the number of questions he attempts correctly, is:

A Woman’s downstream swimming rate is thrice of her upstream swimming rate. If she covers 12 km upstream in 2.5 hours, what distance she will cover in 5 hours downstream?

The mean of a distribution is 15 and the standard deviation is 5. What is the value of the coefficient variation?

Two boxes contain 4 and 16 balls respectively. Two balls in the first box and four in the second, are black. If a box is chosen randomly and two balls are drawn at random from it, what is the
probability that at least one ball is black if the ball is not replaced?