What does 9e+10 mean on a calculator?

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

Acourt reporter is transcribing an accident report from germany. the report states that the driver was traveling 80 kilometers per hour. how many miles per hour was the driver traveling?

15 and 14.7 are 1 apart, so 15 – 14.7 must be 1.