Plz me get the answer to these asap

The ratio of blue cards to green cards is 2 to 5. there are 8 blue cards. complete the diagram and explain how you can find the number of green cards.

What is the value of y? round to the nearest tenth

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