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primary 6 | Maths | Ratio
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Zi qi
Zi Qi

primary 6 chevron_right Maths chevron_right Ratio chevron_right Singapore

Please help!!i try this so many times ,but i can't solve it ! Please help me !!

Date Posted: 4 years ago
Views: 245
Eric Nicholas K
Eric Nicholas K
4 years ago
50-dollar, 20-dollar and 10-dollar tickets are in the ratio 1:6:3 and their total value is $1600.

Let the number of 50-dollar notes be 1 unit. Then the number of 20-dollar notes is 6 units and the number of 50-dollar notes is 3 units.

Total value of 50-dollar notes
= 50-dollar x 1 unit
= 50 dollar-units

Total value of 20-dollar notes
= 20-dollar x 6 units
= 120 dollar-units

Total value of 10-dollar notes
= 10-dollar x 3 units
= 30 dollar-units

Total value of all the notes
= 50 + 120 + 30
= 200 dollar-units

This corresponds to a total of $1600.

200 dollar-units = $1600
1 dollar-unit = $1600/200 = $8

50 dollar-units = $8 x 50 = $400
120 dollar-units = $8 x 120 = $960
30 dollar-units = $8 x 30 = $240

Number of 50-dollar notes
= 400/50
= 8

Number of 20-dollar notes
= 960/20
= 48

Number of 10-dollar notes
= 240/10
= 24

*******************************

Now, she sold 1/3 of the 10-dollar notes and some 20-dollar notes. No 50-dollar notes have been sold away. The 50-dollar notes make up 2/13 of the total number of notes at the end.

Since she sold 1/3 of the 10-dollar notes, she must have sold 1/3 x 24 = 8 pieces of 10-dollar notes.

There are 8 pieces of 50-dollar notes and this makes up 2/13 of the total number of notes at the end.

2 units = 8 pieces
1 unit = 8/2 = 4 pieces
13 units = 4 x 13 = 52 pieces
11 units = 4 x 11 = 44 pieces

So there are a total of 44 pieces of 10-dollar and 20-dollar notes at the end.

Compare this with the 48 + 24 = 72 pieces of 10-dollar and 20-dollar notes at the start.

This shows that a total of 72 - 44 = 28 pieces of 10-dollar and 20-dollar notes have been sold.

But earlier we found that 8 pieces of 10-dollar notes have been sold.

Number of 20-dollar notes sold
= 28 - 8
= 20

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AC Lim
Ac Lim's answer
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