Mrs Yee had a total of 110 white and yellow daisies in the ratio of 8 : 3. After she had given away 3 times as many white daisies as yellow daisies, the number of white and yellow daisies left was in the ratio of 7 : 3. How many more white daisies than yellow daisies did she give away?

	White	Yellow	Total
Before	8 b	3 b	11 b
Change	- 3 u	- 1 u
After	7 p	3 p

	Make p the same (1)x3 = (3)	White (1)	Yellow (2)	Make p the same (2)x7 = (4)
Before	240	80	30	210
Change	- 9 u	- 3 u	- 1 u	- 7 u
After	21 p	7 p	3 p	21 p

Number of daisies at first
= 8 b + 3 b
= 11 b

11 b = 110

1 b = 110 ÷ 11 = 10

Number of white daisies at first
= 8 b
= 8 x 10
= 80

Number of yellow daisies at first
= 3 b
= 3 x 10
= 30

80 - 3 u = 7 p --- (1)

30 - 1 u = 3 p --- (2)

Make p the same.

(1)_x3 
240 - 9 u = 21 p --- (3)

(2)_x7 = (4)
210 - 7 u = 21 p --- (4)

(3) = (4)
240 - 9 u = 210 - 7 u
9 u - 7 u = 240 - 210
2 u = 30

1 u = 30 ÷ 2 = 15

Number of more white daisies than yellow daisies that she gave away
= 3 u - 1 u
= 2 u
= 2 x 15
= 30

Answer(s): 30