Quantitative Aptitude - Arithmetic Ability Questions

If a-1a=1, then a2 + 1a2 ?

Two students appeared for an examination. One of them secured 26 marks more than the other and his marks were 75% of the sum of their marks. The marks obtained by them are

A shopkeeper marks the price of an article at Rs. 320. Find the cost price if after allowing a discount of 10%, he still gains 20% on the cost price.

ΔXYZ is similar to ΔPQR. If ratio of Perimeter of ΔXYZ and Perimeter of ΔPQR is 16:9 and PQ = 3.6 cm, then what is the length(in cm) of XY?

If a+b+c=15 and 1a+1b+1c=71abc, then the a3+b3+c3-3abc is

If x = a + 1a, y = a - 1a ,(a>0), then the value of x4+y4-2x2y2 is

If Sinx = 4/5, then Sec2x - 1 = ?

Select the odd word/letters/number/number pair from the given alternatives.