The rate of interest for the first 2 years is 6% p.a., for the next 3 years is 10% p.a., and for the period beyond 5 years is 12% p.a. If a person gets ₹12,771 as simple interest after 7 years, then how much money did he invest?

A cylindrical roller made of iron is 1.2 m long. Its internal radius is 24 cm and thickness of the iron sheet used in making the roller is 15 cm. What is the mass (in kg) of the roller, if 1 cm³ of iron has 8 g mass?

A hemispherical tank full of water is emptied by a pipe at the rate of 7.7 litres per second. How much time (in hours) will it take to empty $$2\over 3$$ part of the tank, if the internal radius of the tank is 10.5 m?

The circumference of the base of a cylindrical vessel is 158.4 cm and its height is 1 m. How many litres of water can it hold (correct to one decimal place)?

(Take π = 22/7)

A dealer marks his goods at 40% above the cost price. He sells 60% of the goods at the marked price giving 10% discount and the rest by giving 50% discount on the marked price. What is his overall profit/loss per cent?

The number of students in section A and section B of a class are 40 and 52, respectively. The average score in mathematics of all the students is 75. If the average score of the students in A is 20% more than that of students in B. then what is the average score of students is B?

 if $$\sqrt { 11- 3\sqrt { 8}}=a+b\sqrt { 2}$$, then what is the value of (2a+3b)?

From the top of a hill 240 m high, the angles of depression of the top and bottom of a pole are 30° and 60°, respectively. The difference (in m) between the height of the pole and its distance from the hill is: