Respuesta :

Answer:

19 Black Buttons

Step-by-step explanation:

1/4 of 40= 10

1/5 of 40= 8

10+8=18

18+4=21

So there are 21 white grey and orange.

The rest are black so 40-21=19

So 19 black buttons

Hope this helps

eliy05

Step-by-step explanation:

40 button

1/4×40=10 white

1/5×40=8 grey

4 orange

Total=22

Then,subtract

40-22

=18 black buttons