What can go in to the number 5?

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?

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

Math question.. plz me .. best answer all