Martha and steve have 95 colored pencils. if martha has 4 times as many as steve, how many does steve have

Kelly is three years younger than her sister. the sum of their ages is 34 years. how old is kelly and how old is her sister?

I’m stuck on this i don’t understand.

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