In july in Seattle, the grass grows 1/2 in a day on a sunny day, and 1/4 in a day on a cloudy day . In seattle in July, 75% of the days are sunny and 25% are cloudy,

A) determine the expected amount of grass growth on a typical day in July in Seattle

B) determine the expected total grass growth in the month of july in seattle

Question

In july in Seattle, the grass grows 1/2 in a day on a sunny day, and 1/4 in a day on a cloudy day . In seattle in July, 75% of the days are sunny and 25% are cloudy, 

A) determine the expected amount of grass growth on a typical day in July in Seattle

B) determine the expected total grass growth in the month of july in seattle

anonymous · Answer

If a "typical" day in Seattle is considered to be a day that happens most often, then the probability of the day being sunny is 3/4.  If the day is sunny, 1/2 inch is expected to grow.  In a month, there are (assuming) 30 days.  3/4 of those days will have 1/2 inch of growth EACH and 1/4 of those days will have 1/4 inch of growth EACH.

So:  ((3/4 * 30) * (1/2)) + ((1/4 * 30) * (1/4)) should give the amount of growth in a month.

anonymous · Answer

Thank you, what would a typical day be,  (( .75 *30)* (1/2)) ?

anonymous · Answer

a typical day would be simply 1/2 inch.  A "typical" day would be defined as taking place most often.  Since 3 out of 4 days will be sunny, you could assume that a typical day would be sunny.  For a sunny day, 1/2 inch of grass grows, thus 1/2 inch grows on a typical day.