Mrs Ng had a total of 70 pink and yellow tulips in the ratio of 5 : 2. After she had given away 6 times as many pink tulips as yellow tulips, the number of pink and yellow tulips left was in the ratio of 4 : 3. How many more pink tulips than yellow tulips did she give away?

	Pink	Yellow	Total
Before	5 b	2 b	7 b
Change	- 6 u	- 1 u
After	4 p	3 p

	Make p the same (1)x3 = (3)	Pink (1)	Yellow (2)	Make p the same (2)x4 = (4)
Before	150	50	20	80
Change	- 18 u	- 6 u	- 1 u	- 4 u
After	12 p	4 p	3 p	12 p

Number of tulips at first
= 5 b + 2 b
= 7 b

7 b = 70

1 b = 70 ÷ 7 = 10

Number of pink tulips at first
= 5 b
= 5 x 10
= 50

Number of yellow tulips at first
= 2 b
= 2 x 10
= 20

50 - 6 u = 4 p --- (1)

20 - 1 u = 3 p --- (2)

Make p the same.

(1)_x3 
150 - 18 u = 12 p --- (3)

(2)_x4 = (4)
80 - 4 u = 12 p --- (4)

(3) = (4)
150 - 18 u = 80 - 4 u
18 u - 4 u = 150 - 80
14 u = 70

1 u = 70 ÷ 14 = 5

Number of more pink tulips than yellow tulips that she gave away
= 6 u - 1 u
= 5 u
= 5 x 5
= 25

Answer(s): 25