Mrs Quek had a total of 144 pink and yellow daisies in the ratio of 7 : 2. After she had given away 4 times as many pink daisies as yellow daisies, the number of pink and yellow daisies left was in the ratio of 10 : 3. How many more pink daisies than yellow daisies did she give away?

	Pink	Yellow	Total
Before	7 b	2 b	9 b
Change	- 4 u	- 1 u
After	10 p	3 p

	Make p the same (1)x3 = (3)	Pink (1)	Yellow (2)	Make p the same (2)x10 = (4)
Before	336	112	32	320
Change	- 12 u	- 4 u	- 1 u	- 10 u
After	30 p	10 p	3 p	30 p

Number of daisies at first
= 7 b + 2 b
= 9 b

9 b = 144

1 b = 144 ÷ 9 = 16

Number of pink daisies at first
= 7 b
= 7 x 16
= 112

Number of yellow daisies at first
= 2 b
= 2 x 16
= 32

112 - 4 u = 10 p --- (1)

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

Make p the same.

(1)_x3 
336 - 12 u = 30 p --- (3)

(2)_x10 = (4)
320 - 10 u = 30 p --- (4)

(3) = (4)
336 - 12 u = 320 - 10 u
12 u - 10 u = 336 - 320
2 u = 16

1 u = 16 ÷ 2 = 8

Number of more pink daisies than yellow daisies that she gave away
= 4 u - 1 u
= 3 u
= 3 x 8
= 24

Answer(s): 24