Fifty less than three times a number is -20. Find the number.

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)

chad should not have included the values (1, 2) and (3, 6) because that would mean he only had half a healing card.