* Suppose commute times in a large city are normally distributed and that 66.60% of commuters in this city take more than 20 minutes to commute one way. If the standard deviation of such commutes is 6.4 minutes, what is the mean commute? (Round to 3 decimal places)

Ans wrong: 17.254

* Assume a normal distribution and find the following probabilities. (Round to 2 decimal) P( 15 < x <23 | =21 and =3)

Ans wrong: 0.72