Posted by Jordan on .
The average length of time, per week, that students at a certain university spend on homework is normally distributed with a mean of 24.3 hours and a standard deviation of 1.4 hours. Jane tells her parents she spends more time studying than 75% of the students on campus. How many hours per week must Jane spend on homework for this to be true?

Mathone more 
MathMate,
Use normal distribution,
σ=1.4,
μ=24.3
Look up
z=Zscore for onetail distribution for 0.75
Hours = μ+z*σ