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primary 6 | Maths | Ratio
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Jong
Jong

primary 6 chevron_right Maths chevron_right Ratio chevron_right Singapore

Pls help me asap

Date Posted: 4 weeks ago
Views: 17

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Anonymous
Anonymous's answer
115 answers (A Helpful Person)
1st
Hope this helps
Before buying the $45 book,
Ratio of Grace $ : Chris $ : Total $ : Difference
= 3 : 7 : 10 : 4
After buying the $45 book,
Ratio of Grace $ : Chris $ : Total $ : Difference
= 1 : 4 : 5 : 3
Now since they each bought a book of the same cost, the amount spent is the same. So the difference between their money left and difference between their money at first is the same. It doesn't change.
We have to make the differences for each ratio to become the same.
Common multiple of 4 and 3 is 12 because 4 x 3 = 12
Multiply by 3, Ratio of Grace $ : Chris $ : Total $ : Difference before buying book
= 9 : 21 : 30 : 12
Multiply by 4, Ratio of Grace $ : Chris $ : Total $ : Difference after buying book
= 4 : 16 : 20 : 12
9 - 4 = 5, and 21 - 16 = 5. So they each spent 5 units on the book.
5 units = $45 so 1 unit = $45 ÷ 5 = $9
Total amount they had at first = 30 units
= $9 x 30 = $270
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J
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192 answers (A Helpful Person)