Answer:
a) 45
b) 8
Explanation:
There are a couple of ways to look at this.
1) Looking at the ratio, you can figure one number from the other.
2) Find what number the ratio must be multiplied by to give the ratio numbers you need
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a)
The ratio tells you the number of children is 9 times the number of adults. If there are 5 adults, there can be 9×5 = 45 children.
You recognize that multiplying the number of adults by 5 will give 5 adults. Then multiplying the number of children by 5 will give the corresponding number of children:
1 : 9 = 5 : 45 (both numbers multiplied by 5)
There can be 45 children.
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b)
The number of adults needed is 1 for every 3 children, or 1/3 of the number of children. When there are 24 children, 1/3×24 = 8 adults are needed.
We recognize that 24 is 3 times 8, so the ratio must be multiplied by 8 to make the children number match:
1 : 3 = 8 : 24 (both numbers multiplied by 8)
8 adults are needed.