The manager of a sawmill wants to find out what percentage of the boards that the mill produced are defective.

which sampling methods are likely to be biased?

choose all answers that are correct.

a. the manager selects 20 boards at random each day for 5 days and examines them.

b. the manager sends an email to 20 customers who buy lumber from the mill, asking each how many of the boards they bought the past week were defective. results from the first 5 customers to respond are tallied.

c. on 1 day, an hour after the sawmill begins production, 30 boards in a row are selected and examined.

d. every 40th board produced over the course of 1 week is selected and examined.

use an equation of ratios to determine the amount of gas needed to fill the tank.

    0.2             0.8

  =    

288.75             x

                                                              231 gal

so, 0.2x = (0.8)(288.75 gal), and x = = 1155 gal.

                                                                0.2

it would take 1155 gal. to fill the tank.

the cost would be

1155 gal         $3

* = $3465   (answer)

      1           1 gal

hope this you

62.5 paisa

step-by-step explanation:

4000*70 = 280000

280000-(2000*90) = 100000

4000-2400 = 1600

100000/1600 = 62.5

( give brainliest)