Quantitative Aptitude - Arithmetic Ability Questions

An article was sold at Rs. 950 allowing 5% discount on the marked price. The marked price of the article is

If price of the table is increased by 25%, then a person can buy 25 table less for Rs 25000. What is the original price (in Rs) of the table?

A man can row his boat at a speed of speed of 4 kmph and he finds that the time taken rowing upstream is double to that taken downstream. Find the speed of the stream (in kmph).

If Data Interpretation and Modern Maths were taught for a combined time of 96 hours, then for how much time (in hours) were Number system and Geometry
taught?

If 2y cosθ = x sinθ and 2x secθ - y cosecθ = 3 then what is the value of x2+4y2

If {12(a-b)}2+ab=p(a+b)2, then the value of p is 

65.The angles of elevation of an aeroplane flying vertically above the ground, as observed from the two consecutive stones, 1 km apart; are 45o and 60o. The height of the aeroplane from the ground is

Robin can do a work in 10 hours. Pradeep and Robin together can do the same work in 4 hours. Pradeep and Nitin together can do the samework in 5 hours. In how many hours Nitin alone can complete the same work?