Abook with 1400 pages has 700 typos. under assumptions that one should find reasonable, determine the probability that a page has 2 typos.

assuming you meant "Typos in a book," haha.

You should use the Poisson distribution. The Poisson distribution is appropriate when there are a fixed large number of trials in a given interval (a page, in this case) and each trial has a fixed (usually low) probability. The product of the number of trials and the probability of success (or typo) in each trial is the rate λ of the Poisson distribution.

ETA: In the limit, as λ increases without bound, the distribution does approach a normal distribution. At λ=10, here, the difference is not profound, but it's still more appropriate to use the Poisson distribution.

In actual fact, since the number of characters on a page (i.e., the number of trials on a page) is finite, it might be even more appropriate to use a binomial distribution. However, the difference between the binomial distribution and the Poisson distribution is not significant at this scale, and the Poisson distribution is far easier to compute.

sonar - device which is used to find the submit submarines, sankalp ship. sonar waves consists of a transmitter and detector which are installed in the observation centre on board of a ship. the ultrasonic waves are sent into the sea at high frequency about 1000 khz in all direction.

total distance/total time

(85 + 82)/(5+3)

167/8

20 just over