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secondary 4 | E Maths
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Wesley
Wesley

secondary 4 chevron_right E Maths chevron_right Singapore

help pls

Date Posted: 4 years ago
Views: 237

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
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Something like this will be good.

Sorry for the messiness, I got careless at first which led to the rejection of both my answers.

The reason why "18/19" is cancelled in the question is that the quadratic equation (39x - x^2)/380 = 18/19 will soon reduce to the equation x^2 - 39x + 360 = 0 with solutions x = 24 and x = 15, both of which would have to be rejected since 15 blue pens + 6 red pens = 21 pens which already exceed the 20 pen count.
Eric Nicholas K
Eric Nicholas K
4 years ago
Let me know if you need further explanation or you need me to do up tree diagrams for better visualisation.