Item 19 Your pump empties the water from a swimming pool in 6 hours. When your friend's pump is used together with your pump, the pool is emptied in 1.5 hours. How long (in hours) does it take your friend's pump to empty the pool when working alone

0.75 hours

Step-by-step explanation:

Time taken by my pump = 6 hours

Time taken by friend's pump = x

Combined time = 1.5 hours

Rate :

my pump = 1/6

Combined rate = 1/1.5

Combinwd rate = 1/6 + 1/x

Hence :

1/6 + 1/x = 1/1.5

(x + 6) / 6x = 1.5

x + 6 = 9x

x - 9x = - 6

-8x = - 6

x = - 6 / - 8

x = 0.75 hours

22

step-by-step explanation:

22

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