Originally Posted by

**lalalamaths** please help me! i am a little bit stuck!

a farmer supplies tomatoes to a grocery, with an average weight of 74 grams

weight of tomatoes is normally distributed about their mean

grocery has policy of rejecting tomatoes that weigh less than 70 grams

11% of the farmer's tomatoes have been rejected

what is the standard deviation?

i know z=(x-mean)/stdev, x=70, mean=74, P(X<70)=0.11 but i'm totally mind-blanking on how to find z and also stdev.

i think P(x<70)=P(Z<z), is that right?

any help is very much appreciated!

many thanks!!