One supermarket sold 72 cases of Zing soap, but only one-third as many cases of Essence soap. If each case holds 156 bars of soap, how many bars were sold in all? show how you got it

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