Jawab:

21

Penjelasan dengan langkah-langkah:

Known Variables:

- 3/7 of the beads are red

- 1/3 of the beads are yellow

- The rest of the beads are green

- There are 20 more red beads than green beads

I am not sure if this is the fastest way but it works

We are going to solve this via comparison method

3/7 of total : 1/3 of total : 3/7 of total - 20

We can substitute a number that can make a complete number, You might think (3 x 7 or 21) is the right number, but if we use that, the green beads would be negative

3/7 x 21: 1/3 x 21 : 3/7 x 21 - 20

3 x 3 : 7 : 9-20

So we need to find the any number that is higher than 20 once applied 3/7, since 42 is not enough, 49 and 56 is not divisible by three, 63 is our number, thus;

3/7 x 63: 1/3 x 63 : 3/7 x 63 - 20

27 : 21 : 27-20

27 : 21 : 7

Why did I say any in the first place? Lets take an example if we use something bigger like 126,

3/7 x 126: 1/3 x 126 : 3/7 x 126 - 20

54 : 42 : 54-20

(We shouldn't subtract it since if we subtract it before we simplify it, it would be -10 in effect, -5 the next, etc.)

Since all are divisible by 2 (54 : 42 : 54), Ignore the 20 for now

27 : 21 : 27, now since it can't be divided anymore, decrease the last one with 20

27 : 21 : 27 - 20

27 : 21 : 7 (Same answer)

Now we know that:

Red beads: 27

Yellow beads: 21

Green beads: 7

This took some time to write, if you don't mind, please make this the best answer ^^