Mrs Chan had a total of 88 yellow and white daisies in the ratio of 7 : 4. After she had given away 3 times as many yellow daisies as white daisies, the number of yellow and white daisies left was in the ratio of 4 : 3. How many more yellow daisies than white daisies did she give away?

	Yellow	White	Total
Before	7 b	4 b	11 b
Change	- 3 u	- 1 u
After	4 p	3 p

	Make p the same (1)x3 = (3)	Yellow (1)	White (2)	Make p the same (2)x4 = (4)
Before	168	56	32	128
Change	- 9 u	- 3 u	- 1 u	- 4 u
After	12 p	4 p	3 p	12 p

Number of daisies at first
= 7 b + 4 b
= 11 b

11 b = 88

1 b = 88 ÷ 11 = 8

Number of yellow daisies at first
= 7 b
= 7 x 8
= 56

Number of white daisies at first
= 4 b
= 4 x 8
= 32

56 - 3 u = 4 p --- (1)

32 - 1 u = 3 p --- (2)

Make p the same.

(1)_x3 
168 - 9 u = 12 p --- (3)

(2)_x4 = (4)
128 - 4 u = 12 p --- (4)

(3) = (4)
168 - 9 u = 128 - 4 u
9 u - 4 u = 168 - 128
5 u = 40

1 u = 40 ÷ 5 = 8

Number of more yellow daisies than white daisies that she gave away
= 3 u - 1 u
= 2 u
= 2 x 8
= 16

Answer(s): 16