Posted by Tom 6 on Saturday, June 15, 2013 at 4:50pm.
The weights of ripe watermelons grown at Mr. Smith's farm are normally distributed with a standard deviation of 2 lb. Find the mean weight of Mr. Smith's ripe watermelons if only 5% weigh less than 18 lb. (Give your answer correct to one decimal place.)
Incorrect: Your answer is incorrect. . 8.8 lb
I have tried this one several times and can not get it right, please help!!!!!

Math Help and check  Steve, Saturday, June 15, 2013 at 7:18pm
.05 is P(Z<1.645)
That is, 18 is 1.645 std below the mean.
So, the mean is 18+2*1.645 = 21.29