J's answer to Daphne's Primary 6 Maths Ratio Singapore question.
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Amount each had in the end = $332.80 ÷ 2 = $166.40
Let amount Jack spent be 1u
Amount Bill received = 4u
So, Jack's money at first = $166.40 + 1u
Bill's money at first = $166.40 - 4u
Their difference at first = 4u + 1u = 5u
But, Jack had 3 times of Bill's $ at first.
Their difference at first = 2 times of Bill's $ at first
So 2 times of Bill = 5u
Bill's $ at first = 5u ÷ 2 = 2½u
Jack's $ at first = 2½u × 3 = 7½u
Jack's money in the end = 7½u - 1u = 6½ u
6½ u = $166.40
1u = $166.40 ÷ 6½ = $25.60
a)Fraction of his money that Jack spent = 1 / 7½ = (1×2) / (7½×2) = 2/15
b) Amount that Bill received = 4u = 4 × $25.60 = $102.40
Let amount Jack spent be 1u
Amount Bill received = 4u
So, Jack's money at first = $166.40 + 1u
Bill's money at first = $166.40 - 4u
Their difference at first = 4u + 1u = 5u
But, Jack had 3 times of Bill's $ at first.
Their difference at first = 2 times of Bill's $ at first
So 2 times of Bill = 5u
Bill's $ at first = 5u ÷ 2 = 2½u
Jack's $ at first = 2½u × 3 = 7½u
Jack's money in the end = 7½u - 1u = 6½ u
6½ u = $166.40
1u = $166.40 ÷ 6½ = $25.60
a)Fraction of his money that Jack spent = 1 / 7½ = (1×2) / (7½×2) = 2/15
b) Amount that Bill received = 4u = 4 × $25.60 = $102.40
Date Posted:
3 years ago
I dont understand after this part of the answer :
Their difference at first = 2 times of Bill’s $ at first.
Their difference at first = 2 times of Bill’s $ at first.
It should be fairly obvious.
Jack had 3 times of Bill's $ at first.
We can say Jack has 3 parts, Bill has 1 part.
Their difference = 3 parts - 1 part = 2 parts
2 parts is twice of Bill's $ at first.
Jack had 3 times of Bill's $ at first.
We can say Jack has 3 parts, Bill has 1 part.
Their difference = 3 parts - 1 part = 2 parts
2 parts is twice of Bill's $ at first.
But we also know that their difference is also 5 units.
So 5 units = 2 parts
1 part = 5 units ÷ 2 = 2½ units
Is that clearer?
So 5 units = 2 parts
1 part = 5 units ÷ 2 = 2½ units
Is that clearer?
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