Let a and b are two unit vectors such that a + 2b and 5a – 4b are perpendicular. What is the angle between a and b?

Two dice each numbered from 1 to 6 are thrown together. Let A and B…

Two dice each numbered from 1 to 6 are thrown together. Let A and B…

An urn contains one black ball and one green ball. A second urn contains one…

An urn contains one black ball and one green ball. A second urn contains one…

What is the most probable number of successes in 10 trials with probability of success…