Who has the most point in 100 point for whomever tells me and a brainlist if corect

When using the linear combination metho e linear combination method to solve a system of linear equations, the four options are:

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

The holiday party will cost $160 if 8 people attend. if there are 40 people who attend the party, how much will the holiday party cost