Question

You make a necklace with blue, purple, and green beads in a ratio of 1:1:2. Total of 168 beads. How many green beads are there?

Answer 1

If they are in the ratio of 1:1:2 then you have x blue, x purple and 2x green.

x + x + 2x = 168
4x = 168
x = 168 / 4
x = 42

So both blue and purple are 42 and green is 84
Check
42 + 42 + 84 = 168 which checks. 

Answer 2

Blue= 1/4
purple= 1/4
green 1/2
168/4 =42
blue= 42 beads. purple= 42 beads. green= 84 beads
there is a total of 84 green beads.