Quantitative Aptitude - Arithmetic Ability Questions

In ΔABC, D and E are points on side AB and AC respectively. DE is parallel to BC. If lengths of AD, DB and AE are 8 cm, 4 cm and 12 cm respectively, what is the length of AC?

If a3+ b3 = 19 and a + b = 1, then what is the value of ab?

A vendor buys 6 bananas for Rs 25 and sells them at 3 for Rs 20. What is his profit percentage?

A mason can build a wall in 70 hours. After 7 hours he takes a break. What fraction of the wall is yet to be built?

Chords PQ and RS of a circle extended externally intersect at point T. Length of the segment PT, if lengths of QT, RT and ST are 9 cm, 18 cm and 6 cm respectively, is

Rs. 750 invested for 3 months gave an interest of Rs. 18. What was the simple rate of interest per annum?

If a3 + b3 = 28 and a + b = 4, then what is the value of ab?

If a = 1/a-5, then the value of a + 1/a = ?