Ruth Sin's answer to blur blur's Secondary 1 Maths Singapore question.

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Ruth Sin
Ruth Sin's answer
50 answers (A Helpful Person)
1st
Easiest way is to just find the rate of each person and compare.

If concept of rate alludes you, then you can use a comparison chart to find for the same number of planes, how long each person needs to fold them. Compare 2 people first and use the faster person to compare with the third person.