Quantitative Aptitude - Arithmetic Ability Questions

Two students appeared for an examination. One of them secured 9 marks more than the other and his marks were 56% of the sum of their marks. The marks obtained by them are

What is the value of 2 - 2z + z22 + 2z - z2, when z+2z = 2 ?

If the shopkeeper sells an item at Rs 450 which is marked as Rs 600, then what is the discount he is offering?

A train travelling at 76 kmph crosses a 450 m long platform in 27 seconds. What is the length of the train?

Find the range of the data : 11,13, 9, 17, 13, 19, 10, 11

When Gopal walks from A to B and returns from B to A on cycle, then it takes him 46 minutes. By walking both ways, it takes him 75 minutes. If he rides cycle both ways then what will be the total time (in minutes)?

A, B and C can do a job working alone in 6, 9 and 18 days respectively. They all work together for 1 day, then A and B quit. How many days C working alone will take to complete the remainder of the job?

The average marks obtained by a group of 10 students were 20. One student left the group as a result of which the average of the remaining students rose to 21. But another student joined, as a result of which the average marks of the group dropped a bit and became 20.6. What were the average marks obtained by the student who left and the one who joined?