Yxcas's answer to SC's Primary 6 Maths Singapore question.

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Yxcas
Yxcas's answer
184 answers (A Helpful Person)
1st
Let the coins Mary have in the end be 6x where x is a multiplier to convert the ratio units to actual number of coins.
(6x - 20) / (7x + 20) = 3 / 4
4(6x - 20) = 3(7x + 20)
24x - 21x = 60 + 80
3x = 140
6x = 280
Mary have 280 coins in the end.
JC
JC
2 months ago
Thank you!