What’s the size of angle x

Plz which expression is equivalent to the expression below?

Julia chooses a card at random from her set of cards. what is the probability that the card is labeled cat or hamster?

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