Quantitative Aptitude - Arithmetic Ability Questions

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?

What will be the net discount (in %) of two successive discounts of 15% and 35%?

If a – (1/a) = b, b – (1/b) = c and c – (1/c) = a, then what is the value of (1/ab) + (1/bc) + (1/ca)?

The sum of the ages of Ram and Shyam is 49. The difference between the age of Shyam and twice the age of Ram is 8. What is the age (in years) of Ram?

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?

What is the value of [1 – tan (90 – θ) + sec (90 – θ)]/[tan (90 – θ) + sec (90 – θ) + 1]?

If 2/3(6x/5 - 1/4) + 1/3 = 9x/5, then what is the value of x?

The average of marks of 17 students in an examination was calculated as 71. But it was later found that the mark of one student had been wronglyentered as 65 instead of 56 and another as 24 instead of 50. The correct average is