Find the exact value of cos 120⁰.

The centroid of an equilateral triangle PQR is L. If PQ = 6 cm, the length of PL is:

For a sample data, mean = 60 and median = 48. For this distribution, the mode is:

The difference between the length of two parallel sides of a trapezium is 12 cm. The perpendicular distance between these two parallel sides is 60 cm. If the area of the trapezium is 1380 cm², then find the length of each of the parallel sides (in cm).

In 5 years, the simple interest on an amount of Rs. X is $$2\over 5$$ of the principal. The rate of interest per annum is:

The probabilities of solving a problem by three students A, B and C are  $$3\over 7$$, $$5\over 9$$ and $$1\over 5$$ respectively. The probability that problem will be solved is:

Simplify the following

  $${\sqrt { 10+{\sqrt { 25+ {\sqrt { 108 +\sqrt { 154+ \sqrt { 225} \ } \ } \ }} \ } } \ }\over \sqrt { 16+ 19.25×4^2} $$

If the highest common factor (HCF) of x and y is 15, then the HCF of 36x² – 81y² and 81x² – 9y² is divisible by __________