The value of $$cos^{2}$$90°- $$sin^{2}$$90° is

A person purchased 15 pens and 30 books worth Rs. 825. If the cost of a book is double that of a pen, calculate the cost of the one book.

Find the missing number in the following series.
7, 10, 14, ?, 25, 32

A person driving at the speed of 40 kmhr reaches office 1 minute early while he reaches 3 minutes late if driving at 36 km/hr. Whatis the distance (in km) that she is covering?

Read the given statement and the following conclusions carefully and select which of the conclusions logically follow(s) from the statement.
Statement:
"These pictures are awesome", says the photographer appreciating his assistant.
Conclusions:
I. The assistant has done a good job.
II. The photographer is much pleased with his assistant's work