Cost price of 25 chairs equals the selling price of 20 chairs. Find the profit %.

The largest and the second largest angles of a triangle are in the ratio of 3 : 2 respectively. The smallest angle is 20% of the sum of the rest two angles. What is the sum of the smallest and the second largest angles?

Salim's age is 10 years. His grandfather's age is 62 years. After how many years will his grandfather's age be five times that of Salim?

If $${a+b=10}$$ and $$ \sqrt{a\over b}-13=-\sqrt{b\over a}-11$$, then what is the value of $${3ab+4a^2+5b^2}$$?

The maximum number of common tangents drawn to two circles when both the circles touch each other externally is 

If the numerator of a fraction is increased by 250% and the denominator is increased by 400%. The resultant fraction is7/19 . What is the original fraction?

Ramiya got married 8 years ago. Her present age is 6/5 times her age at the time of her marriage. Ramiya’s brother was 10 years younger than her at the time of her marriage. What is the ratio of Ramiya’s present age and her brother’s age at the time of her marriage?

A cistern has 3 pipes A, B and C. A and B can fill it in 3 and 4 hours respectively, and C can empty it in 1 hour. If the pipes are opened at 3 p.m., 4 p.m. and 5 p.m. respectively on the same day, the cistern will be empty at-