Quantitative Aptitude - Arithmetic Ability Questions

A trader buys 500 kgs of cotton for Rs 9,000. 10% of this cotton is spoiled due to rain. At what rate (Rs/Kg) should he sell the rest to earn 10% profit?

10 persons can do a job in X days. If 20 persons with twice the efficiency can do the same job in 5 days, then find the value of X?

A and B together do a job in 15 days and A alone could do the same job in 20 days. How many days would B take to do half the job if he worked alone?

A and B can together do a piece of work in 6 days and A alone can do it in 9 days. The number of days B will take to do it alone is

If x+1x = 2, then x2+1x2 = ?

If Rajan purchase 21 pens for Rs 20 and sell all the pens at the rate of 20 pens for Rs 21, then what will be the profit percentage?

A solid cube is cut into 27 identical cubes. What is the percentage increase in the total surface area?

The product of two numbers is 48. If one number equals "The number of wings of a bird plus 2 times the number of fingers on your hand divided by the number of wheels of a Tricycle". Then the other number is