Let
    A = | p q |
      | r s |
where p, q, r and s are any four different prime numbers less than 20. What is the maximum value of the determinant?

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…