(sec A + tan A – 1) (sec A – tan A+1) =?

If $$ {x+{9\over x}=6}$$  then find the value of $$ {x^{2}+{1\over x^{3}}}$$

A work can be completed by 20 men in 50 days. 30 more men join them after 10 days of work. How many days will be saved in completion of the work?

If a seller bought an item for Rs. 900 and determined the mark price in such a way that after giving 10 percent discount, he would get a profit of 20 percent, what would be the mark price?

Read the following graph carefully and answer the related questions-

Total number of students (in thousands) participating in comitative exam in various cities.

What is the ratio of number of students appearing for competitive exam from city C and D together to those appearing from A, D and E together?

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 -

Find the difference between compound interest and simple interest on 5000 for 2 years at 8% p.a payable annually.

If the income of A is 25% more than that of B, then by what percent is the income of B less than that of A?