Why does it not matter what letter or symbol is used to find an unknown number?

Multiply. write your answer in simplest form. 3/8 x 5/7

Find the perimeter of the figure shown above. a. 18 yds c. 20 yds b. 10 yds d. 24 yds select the best answer from the choices provided

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