Ratio

1
Ratio
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Ratio?

• Ratio is a way of comparing two or more
  quantities
• E.g.
• Number of Red Smarties in a box compared to Blue
• Number of girls in a class compared to boys

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For example
RED BLUE Smarties
Blue Red
6 3
2 1
6 BLUE
3 RED
The Ratio of BLUE to RED Smarties is 6 to 3
The Ratio of BLUE to RED Smarties is 21
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. Or
RED BLUE Smarties
Red Blue
3 6
For every RED Smartie, there are 2 BLUES
1 2
6 BLUE
3 RED
The Ratio of RED to BLUE Smarties is 12
The Ratio of RED to BLUE Smarties is 3 to 6
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Simplifying Ratios

• In the Smarties example, we changed 63 to 21
• This is called Simplifying a ratio
• We did it by dividing each number by 3
• 3 was the largest common factor

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Try to simplify these

• 82
• 183
• 48
• 525
• 52

41 61 12 15 52 !!
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Sharing an amount in a given ratio
Bart and Maggie share a bag of 16 sweets in the
ratio 31
This means for every 3 sweets Bart gets, Maggie
gets 1
4
12
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quicker way.
Bart and Maggie share a bag of 16 sweets in the
ratio 31
Another way to think of this 31 is shares
Bart gets 3 shares to Maggies 1
So there are actually 4 shares
16 sweets shared by 4
16 4
4 in a share
1 share
3 shares
1 x 4
3 x 4
4
12