Explain on the basis of the various rules of Exercises 2.5 through 2.9 why there is a mistake in each of the following statements: 

(a) The probability that it will rain is 0.67, And the probability that it will rain or snow is 0.55.

(b) The probability that a student will get a passing grade in English is 0.82, And the probability that she will get a passing grade in English And French is 0.86. 

(c) The probability that a person visiting the SAN Diego Zoo will see the giraffes is 0.72, the probability that he will see the bears is 0.84, And the probability that he will see both is 0.52.