If 0.5x + 0.7y=0.5 and 0.7x + 0.5y=0.7,then the value of x+y is

23+ 3+33+333+3.33=?

Simple interest on a certain sum is equal to the sum itself. find the time if rate of interest and time are numerically equal.

In a school of 1200, students were asked how they travelled to school. The information obtained is depicted by a pie-chart as below. From the given information find how many students come to school by Car? 

The value of $$ {4^{10+n}}.{16^{3n-4}}\over4^{7n}$$ is:

Find the value of given expression.

30 – [40 – {56 – (25 – 13 – 12)}]

A and B under took a work Rs 2200. A alone can do the work in 10 days and B alone can do the work in 12 days. If they work together, then what will be the difference (in Rs) in the amount they receive?  

A tank is 25m long 12m wide and 6m deep. The cost of plastering its walls and bottom at 225 paise per sq m is