Daniel had 132 cards.
34 were grey and the rest were red and white. The ratio of the number of red cards to the number of white cards was 1 : 2. Daniel decided to give away some grey cards to decrease the number of grey cards to half of the total number of cards.
- How many more grey cards than red cards did he have at first?
- How many grey cards did he have to give away?
Grey cards |
Red cards |
White cards |
Total |
3x3 |
1x3 |
|
|
1x1 |
2x1 |
|
9 u |
1 u |
2 u |
132 |
|
Grey cards |
Red cards |
White cards |
Before |
9 u |
1 u |
2 u |
Change |
- ? |
|
|
After |
3 u |
3 u |
Comparing grey, red and white cards in the end |
1 |
1 |
(a)
The total number of red cards and white cards is repeated. Make the total number of red cards and white cards the same. LCM of 1 and 3 is 3.
Total number of cards at first
= 9 u + 1 u + 2 u
= 12 u
12 u = 132
1 u = 132 ÷ 12 = 11
Number of more grey cards than red cards at first
= 9 u - 1 u
= 8 u
= 8 x 11
= 88
(b)
Number of more grey cards that Daniel had to give away
= 9 u - 3 u
= 6 u
= 6 x 11
= 66
Answer(s): (a) 88; (b) 66