In a box,
number of red buttons:
number of blue buttons
= 5: 3

number of blue buttons:
number of green buttons
= 1: 2

there are 48 green buttons in the box.
work out the number of red buttons in the box.

Number of red buttons = 40

Step-by-step explanation:

red : blue = 5:3

blue : green = 1:2

Green is 48.

We find blue first.

blue : green = blue / green

1:2 = 1/2

b - blue

1/2 = b/48

Cross multiply

48 × 1 = 2 × b

48 = 2b

48 ÷ 2 = b

24 = b

Blue : Green = 24 : 48

Now we find red.

red : blue = red / blue

5 : 3 = 5 / 3

r - red

5/3 = r/24

Cross multiply.

5 × 24 = 3 × r

120 = 3r

120 ÷ 3 = r

40 = r

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^

cosine

step-by-step explanation: