AC Lim's answer to M's Primary 6 Maths Algebra Singapore question.
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Use ratio with Bruce remain unchanged.✨Hope this helps
Date Posted:
3 years ago
Reason to change -u to -2u is to make it easier to multiply -2u by 1/2 for Alice?
Can explain why to get how much Alice have, we use 1000 + 6u? If Alice did not spend, shouldn’t she just have 6u? (without 1000)?
Can explain why to get how much Alice have, we use 1000 + 6u? If Alice did not spend, shouldn’t she just have 6u? (without 1000)?
Yes. We try not to use fraction in calculation.
If Alice spend half of what Bruce spends. So, we let Bruce = 2u and Alice = u.
If Alice never spend....
She will have 2200 + u
or
1000 + 6u
From here, we can solve for u...
1000+6u = 2200+u
5u = 2200-1000
1u = 1200 ÷5 = 240.
So, for Alice, can use
2200+u = 2200+240 = 2440
Or
1000+6u = 1000+(6×240) = 2440.
If Alice spend half of what Bruce spends. So, we let Bruce = 2u and Alice = u.
If Alice never spend....
She will have 2200 + u
or
1000 + 6u
From here, we can solve for u...
1000+6u = 2200+u
5u = 2200-1000
1u = 1200 ÷5 = 240.
So, for Alice, can use
2200+u = 2200+240 = 2440
Or
1000+6u = 1000+(6×240) = 2440.
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