Question

the ratio of blue to black pens in a box is 1:3 there are 15 blue pens how many black pens are there?​

Answer 1

Answer:

mark me as brainliest plz

Step-by-step explanation:

Black pens - 5x and blue pens = 8x.

5x:(8x-20) = 5:6, or

30x = 40x-100

10x = 100, or

x = 10

So there were 50 black pens and 80 blue pens to start with.

Answer 2

Answer:

45

Step-by-step explanation:

No of black pens = 3× 15 = 45