The difference between the compound and the simple interest on a sum for 2 years at 10 % per annum , when the interest is compounded annually, is Rs.28. If the yearly interest were compounded half yearly, the difference in the two interests will be 

There are some boys and girls in a room. The square of the number of girls is 28 less than the square of the number of boys. If two more girls join then the number of boys and girls becomes equal, then what is the total number of boys and girls in the room?

5√2 cm in a circle. If the long chord makes a right angle at the centre, then what will be the length of the radius of the circle?

If the simple interest for 6 years be equal to 30% of the principal, it will be equal to the principal after 

The ratio of circumradius and hypotenuse a right-angled triangle is

While selling an article, a shopkeeper gives a discount of 5%. If he gives a discount of 7%, he earns Rs.15 less as profit. The marked price of the article is -

Three solid metallic sphere whose radii are 3cm, x cm and 18cm respectively, are melted and recast into a single solid sphere of diameter 38cm. Then find the total surface area of the sphere with radius x cm?

A pipe can fill a tank in x hours and an another can empty it in y hours. In how many hours will they together fill it. If y>x?