Adam has 140 stickers.
He has 20 less green stickers than blue stickers.
He has 30 less red stickers than green stickers.
How many less red stickers than blue and green stickers does Adam have?
Choose the smallest group to be 1 u.

Number of red stickers = 1 u
Number of green stickers = 1 u + 30
Number of blue stickers = 1 u + 30 + 20 = 1 u + 50

Total number of stickers
= 1 u + 1 u + 30 + 1 u + 50
= 3 u + 80

3 u + 80 = 140
3 u = 140 - 80
3 u = 60

1 u = 60 ÷ 3 = 20

Total number of blue and green stickers
= 1 u + 30 + 1 u + 50
= 2 u + 80

Number of less red stickers than blue and green stickers
= 2 u + 80 - 1 u
= 2 u - 1 u + 80
= 1 u + 80
= 20 + 80
= 100

Answer(s): 100