Z varies directly with the product of x and y, when
x=2,y=0.5, z=4, so the function is z=

z = 4xy

Step-by-step explanation:

IF Z varies directly with the product of x and y, then;

Z = kxy

k is the proportionality constant

If x=2,y=0.5, z=4,

4 = k(2)(0.5)

4 = k * 2 * 1/2

4 = k

Swap

k = 4

Substitute into the original expression

z = kxy

z = 4xy

This gives the required expression

10000

step-by-step explanation: divide by 2,

all three statements are true

step-by-step explanation:

a shipping fee of 5% is charged online with every item purchased online

first let's just take each option and calculate them based on this, to see if the answers matched

keith buys a 40 dollar book

40 x 0.05 = 2

therefore there will be a two dollar fee on keith's book

40 + 2 =42

the first statement is true

a chair costs $80

80 x 0.05 = 4

80 + 4 = 84

the second statement is true

george buys a 20 dollar calculator

20 x 0.05 = 1

20 + 1 = 21

the third statements are true

all three statements are true