J's answer to Merlion's Primary 5 Maths Rate & Ratio Singapore question.
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45kg - 42kg = 3kg
Basically, these two students 'donated' 3kg each to the other students.
3kg × 2 = 6kg, so 6kg was 'donated' to them.
42kg - 40kg = 2kg
The other students 'gained' 2kg each.
Number of students at first = 6kg ÷ 2kg = 3
Basically, these two students 'donated' 3kg each to the other students.
3kg × 2 = 6kg, so 6kg was 'donated' to them.
42kg - 40kg = 2kg
The other students 'gained' 2kg each.
Number of students at first = 6kg ÷ 2kg = 3
Date Posted:
2 years ago
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40kg × 3 = 120kg
45kg × 2 = 90kg
New total = 120kg + 90kg = 210kg
New average = 210kg ÷ 5 = 42kg ✓
40kg × 3 = 120kg
45kg × 2 = 90kg
New total = 120kg + 90kg = 210kg
New average = 210kg ÷ 5 = 42kg ✓
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