Adam has red and green stickers in the ratio of 9 : 7.
He has 90 more red stickers than green stickers.
- How many stickers does Adam have?
- If Adam gives away 20 red stickers, what is the new ratio of the number of red stickers to green stickers?
(a)
Number of red stickers = 9 u
Number of green stickers = 7 u
Number of more red stickers than green stickers
= 9 u - 7 u
= 2 u
2 u = 90
1 u = 90 ÷ 2 = 45
Number of stickers that Adam has
= 9 u + 7 u
= 16 u
= 16 x 45
= 720
(b)
Number of red stickers after Adam gives away 20
= 9 u - 20
= 9 x 45 - 20
= 405 - 20
= 385
Number of green stickers
= 7 u
= 7 x 20
= 315
New ratio of the number of red stickers to green stickers
385 : 315
(÷ 35) 11 : 9
Answer(s): (a) 720; (b) 11 : 9