The average adult human has approximately 2.5 ×1013 red blood cells and 7×109 white blood cells. about how many times as great is the number of red blood cells than the number of white blood cells? write and solve an equation.

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

If c(x) = 4x – 2 and d(x) = x2 + 5x, what is (cxd)(x)

Yoku is putting on sunscreen. he uses 2\text{ ml}2 ml to cover 50\text{ cm}^250 cm 2 of his skin. he wants to know how many milliliters of sunscreen (c)(c) he needs to cover 325\text{ cm}^2325 cm 2 of his skin. how many milliliters of sunscreen does yoku need to cover 325 \text{ cm}^2325 cm 2 of his skin?