In my number the digit in ones place is double the digit in the tens place

Does the problem involve permutations or? combinations? do not solve. the matching section of an exam has 4 questions and 7 possible answers. in how many different ways can a student answer the 4 ? questions, if none of the answer choices can be? repeated?

Use the data on the dot plot to answer the question.how many people read for more than three hours last week? i'm on a unit test review

3x + 4y = 5 x- 3y = -7 solve by substitution