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?

Direction: What value will come in place of the question mark (?) in the following question?

2.4, 3.6, 5.1, 6.9, ?, 11.4

The marked price of an article is 30% higher than the cost price. If a trader sells the articles allowing 10% discount to customer, then the gain per- cent will be

A wateh dealer pays 10% customs duty on a watch which costs Rs. 500 abroad. He de- sires to make a profit of 20% after giving a discount of 25% to the buyer. The marked price should be

If△ABC ∼ △EDF such that AB = 6 cm, DF = 16 cm and DE = 8 cm, then the length of BC is:

Direction: What value will come in place of the question mark (?) in the following question?

100, 108, 120, 136, 156, ?

If 20% of (A+B) = 50% of B, then Value of $${2A-B}\over {2A+B}$$ is 

In the given question, two equations numbered l and II are given. Solve both the equations and mark the appropriate answer.

I. x² - 19x + 60 = 0

II. y²- 20y + 99 = 0