A chemist needs 90 milliliters of a 57% solution but has only 27% and 72% solutions available. Find how many milliliters of each that should be mixed to get the desired solution.

Aproduction manager test 10 toothbrushes and finds that their mean lifetime is 450 hours. she then design sales package of this type of toothbrush. it states that the customers can expect the toothbrush to last approximately 460 hours. this is an example of what phase of inferential statistics