SAT Subject Test Mathematics Level 1

If  the probability that    an  event   will    occur   is  a,  then    the probability that

the event   will    not occur   is  1   −   a.

If  the probability that    one event   will    occur   is  a   and the independent

probability that    another event   will    occur   is  b,  then    the probability that

both    events  will    occur   is  ab.

Example 10

To get the probability that an event will not occur, subtract the probability
that it will occur from 1. The probability that it will rain today is 60%, so the
probability that it will not rain today is 100% − 60% = 40%. The probability
that it will rain tomorrow is 75%, so the probability that it will not rain
tomorrow is 100% − 75% = 25%.

The probability of  rain    today   is  60  percent,    and the independent

probability of  rain    tomorrow    is  75  percent.    What    is  the percent

probability that    it  will    rain    neither today   nor tomorrow?

1.

(A) 10%

(B) 15%

(C) 45%

(D) 55%

(E) 65%