Saturday, September 11, 2010

Ratio P6 2010 SA2 RGS P2 Q16

Irene had a total of 1686 red, blue and green balloons on sale. The ratio of the number of red balloons to the number of blue balloons was 2:3. After Irene sold ¾ of the blue balloons, ½ of the green balloons and none of the red balloons, she had 922 balloons left. How many blue balloons did Irene have at first?[4 marks][Answer given: 948]


R [][][][][][][][]                ]
B [][][][][][][][][][][][]     ] 1686
G [       ][        ]                  ]

20 u + 2 p --> 1686


R [][][][][][][][]   ]
B [][][]                 ] 922
G [      ]                ]

11 u + 1 p --> 922

22 u + 2 p --> 2 x 922 = 1844

2 u --> 1844 - 1686 = 158

12 u --> 12/2 x 158 = 948 blue balloons

It was 948 blue balloons.

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