Adam has 170 stickers.
He has 10 less green stickers than red stickers.
He has 20 less blue stickers than green stickers.
How many less blue stickers than red and green stickers does Adam have?
Choose the smallest group to be 1 u.

Number of blue stickers = 1 u
Number of green stickers = 1 u + 20
Number of red stickers = 1 u + 20 + 10 = 1 u + 30

Total number of stickers
= 1 u + 1 u + 20 + 1 u + 30
= 3 u + 50

3 u + 50 = 170
3 u = 170 - 50
3 u = 120

1 u = 120 ÷ 3 = 40

Total number of red and green stickers
= 1 u + 20 + 1 u + 30
= 2 u + 50

Number of less blue stickers than red and green stickers
= 2 u + 50 - 1 u
= 2 u - 1 u + 50
= 1 u + 50
= 40 + 50
= 90

Answer(s): 90