What is 10 + 10 + 10 + 10 + 10

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

If chord ab is congruent to chord cd, then what must be true about ef and eg?

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39