An alloy has Iron, Silver and Bronze in the ratio 7 : 2 : 3. Another alloy has Silver and Bronze in ratio 1 : 2. In what ratio should the two mixtures be mixed so that the ratio of Iron and Silver in resultant mixture is 5 : 3?

A mathematics teacher calculated the total marks obtained by 35 students of 8th class . The average marks of the students were 72. But 36 marks for Reena was calculated in place of 86 obtained by her. What was the correct average of all the students? 

Thrice the square of a natural number decreased by four times the number is equal to 50 more than the number. The number is :

A ladder rests against a wall at a height of 10 meters. If the ladder makes 30° along the ground. Find the distance from the wall of the foot of the ladder.

If the fractions $$ {9\over11}$$, $$ {7\over9}$$, $$ {5\over6}$$ and $$ {11\over13}$$ are arranged in ascending order, which one will be the fourth?

If tanθ=1/5 then the value of Cosec²θ=?

Speed of current is 10% of speed of boat in still water and the time taken by the boat to cover X km in downstream is 100% more than time taken by the boat to cover (X-45) km in upstream. Find the value of X?

Ratio of the number of sides of two regular polygons is 5 : 6 and the ratio of their each interior angle is 24 : 25. Then the number of sides of these two polygons are