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primary 6 | Maths
| Percentage
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Pls help
Date Posted: 4 years ago
Views: 495
Fractions way :
75% = 75/100 = 3/4
40% = 40/100 = 4/10 = 2/5
Fraction of money Roy had left
= 1 - 3/4 = 1/4
Fraction of money Dennis had left
= 1 - 2/5 = 3/5
Since Dennis had twice as much left as Roy,
We see that the numerator for Dennis is thrice of Roy. So we have to change the numerator to satisfy the above.
1/4 = 3/12
3/5 = 6/10
Now it satisfies the above.
Looking at the denominator, we can say Roy has 12 units at first and Dennis has 10 units at first.
Total = 12 units + 10 units = 22 units
22 units = $660
1 unit = $660 ÷ 22 = $30
Amount Dennis had in the end
= 6 units
= $30 x 6 = $180
75% = 75/100 = 3/4
40% = 40/100 = 4/10 = 2/5
Fraction of money Roy had left
= 1 - 3/4 = 1/4
Fraction of money Dennis had left
= 1 - 2/5 = 3/5
Since Dennis had twice as much left as Roy,
We see that the numerator for Dennis is thrice of Roy. So we have to change the numerator to satisfy the above.
1/4 = 3/12
3/5 = 6/10
Now it satisfies the above.
Looking at the denominator, we can say Roy has 12 units at first and Dennis has 10 units at first.
Total = 12 units + 10 units = 22 units
22 units = $660
1 unit = $660 ÷ 22 = $30
Amount Dennis had in the end
= 6 units
= $30 x 6 = $180
See 1 Answer
Tks so much
How did you derive at 10 unite and 20 units instead of 1:2?
How did you derive at 10 unite and 20 units instead of 1:2?
How did you derive to 10:20 units?
just multiply each by 10. if you’re asking why i choose to do that, it’s because i don’t want to work with too many decimal places. for eg, 10/6 of 20u is not as “ugly” as 10/6 of 2u.
if one is comfortable using fractions/long decimals, this 2:1 to 20:10 conversion can be skipped.
if one is comfortable using fractions/long decimals, this 2:1 to 20:10 conversion can be skipped.
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