In a hostel ration stocked for 400 students upto 31 days. After 28 days 280 students were vacated the hostel. Find the number of days for which the remaining ration will be sufficient for the remaining students.

If $\displaystyle$$\displaystyle \frac{3}{x+y} + \frac{2}{x-y}$ = -1 and $\displaystyle$$\displaystyle \frac{1}{x+y} - \frac{1}{x-y} = \frac{4}{3}$ then $\displaystyle (x, y)$ is:

$\displaystyle \frac{2x+5}{10} + \frac{3x+10}{15} = 5$, find $\displaystyle x$

The cost of $\displaystyle 2$ oranges and $\displaystyle 3$ apples is $28$. If the cost of an apple is doubled then the cost of $3$\displaystyle oranges and$5$ apples is $75$. The original cost of $\displaystyle 7$ oranges and $\displaystyle 4$ apples (in Rs) is:

In a multiple choice question paper consisting of $100$\displaystyle questions of$1\displaystyle mark each, a candidate gets $60\% marks. If the candidate attempted all questions and there was a penalty of $0.25$ marks for wrong answers is:

The values of $\displaystyle x$ and $\displaystyle y$ satisfying the equations $\displaystyle$$\displaystyle \frac{3}{x+y} + \frac{2}{x-y} = 3$ and $\displaystyle$$\displaystyle \frac{2}{x+y} + \frac{3}{x-y} = \frac{23}{3}$ given by