Question

There are 400 beads in a box. 20% of them are red, 35% of them are yellow and the rest are green. How many green beads are there in the box

Answer 1

Answer is 180 green beads
Step by step
Out of 100%, 20% are red and 35% are yellow.
That means 100% - 20% - 35% = 45% are green.
We can multiply 400 beads x 45% to get how many are green ( 45% is the same as .45)

400 x .45 = 180 are green

To check your work,
You already know green beads = 180
Multiply 400 x 20% red beads = 80
Multiply 400 x 35% yellow beads = 140


Add all together 140 + 80 + 180 = 400 beads!
Problem solved.

Answer 2

Explanation:

400 is the whole = 100%

20% (= 20 out of 100 equal parts of 100%) are red.

how many are that ?

well, again, 400 = 100%

1% = 100%/100 = 400/100 = 4

20% = 20×1% = 20×4 = 80

when you combine these 2 steps, you see you get 20% by multiplying the 100% by 20/100 or 0.20.

400 × 0.2 = 80

now,

35% are yellow.

35% = 35×1% = 35×4 = 140

or

400×0.35 = 140

red + yellow = 80 + 140 = 220

the rest are green

400 - 220 = 180

we would get this also by seeing that

red + yellow = 20% + 35% = 55%.

so, green has then the remaining 100-55 = 45%

and again

45% = 45×1% = 45×4 = 180

or

400×0.45 = 180