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question 7a
Question 7a

secondary 2 chevron_right Maths chevron_right Singapore

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Date Posted: 2 years ago
Views: 569

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We can say the ribbon is cut into two pieces, one is p units long and one is q units long.
Total length = (p + q) units
This equals x
1 unit = x/(p + q)
Since p > q, length of the longer piece = p units
= x/(p + q) × p
= px/(p + q)
length of the shorter piece = q units
= x/(p + q) × q
= qx/(p + q)
Difference = length of longer piece - length of shorter piece
= px/(p + q) - qx/(p + q)
= (px - qx)/(p + q)
= x(p - q)/(p + q)
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J
J's answer
1022 answers (A Helpful Person)
1st
J
J
2 years ago
Alternatively,

Total length = (p + q) units

This equals x

1 unit = x/(p + q)

Since p > q, length of the longer piece = p units

length of the shorter piece = q units

Difference = length of longer piece - length of shorter piece

p units - q units
= (p - q) units

The difference as a fraction of the total ribbon length = (p - q)/(p + q)

Since the ribbon is x metres long,

Difference in length = x × (p - q)/(p + q)

= (p - q)x / (p + q)
J
J
2 years ago
Example : lets say p = 5, q = 3, x = 10

We can say longer piece is 5 units, shorter piece is 3 units

Total = 8 units

The longer piece is ⅝ of the total.
The shorter piece is ⅜ of the total.


Length of longer piece

= 10 m × ⅝
= 50/8 m
= 25/4 m
= 6¼ m
= 6.25 m

But this is just equal to 10m × 5/(5 + 3)

Likewise, the length of the shorter piece

= 10 m × 3/(5 + 3)
= 3.75 m or 3¾ m

Difference = 6.25m - 3.75m = 2.5 m

But this is just equal to :

10(5 - 3)/(5 + 3) m

= 10(2) / 8 m

= 10/4 m

= 2¼ m = 2.5 m