OE


The probability of rainfall on at least one of the two days is equal to P(Rain 1st day) + P(Rain 2nd day) - P(Rain both days), since rainfall on each day is independent of what happened on other days. This probability equals: 0.3 + 0.3 - (0.3 x0.3) = 0.6 - 0.09 = O.51 or 51%.

Alternatively, you can use the “1 - x” trick here: rainfall on at least one of the two days is 1 - the probability of rain on either day (0.7^2). Therefore, the probability is 1-0 7 x 0 .7 = 1- 0.49 = 0.31 = 51%.

Quantity B, the probability of no rainfall on either day, follows from the work above: 0.7 x 0.7 = 0.49, which is 49%.Thus. Quantity A is greater.