annissa chan's answer to Jin Jin's Primary 6 Maths Singapore question.
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easier to think of the question in ratios.
initially, area A : area B is 40 : 100.
now, area A : area B is 1:3, since 300% means area B is 3 times of A.
since area A didn’t change, you can view the new ratio as 40:120 (multiply 1:3 by 40 on both sides).
in this sense, area B increased from 100 units to 120 units.
hence, % increase is (120-100) / 100 , multiplied by 100%, aka 20/100 x 100% which gives you 20% as the final answer:))
initially, area A : area B is 40 : 100.
now, area A : area B is 1:3, since 300% means area B is 3 times of A.
since area A didn’t change, you can view the new ratio as 40:120 (multiply 1:3 by 40 on both sides).
in this sense, area B increased from 100 units to 120 units.
hence, % increase is (120-100) / 100 , multiplied by 100%, aka 20/100 x 100% which gives you 20% as the final answer:))
Date Posted:
3 years ago
Thank you, teacher
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