Algebraic solutions are already there, so Lets do it by assuming some values-

whenever you have to assume some values, make sure they in multiple.

It becomes easy to calculate later.say x=$100, c=10, d=5 to reach $100, 10 people have to contribute $10 each.

5 of them did not give their share= 50$ was short

this $50 must be shared by remaining 5 people.

additional share the remaining people have to share= 50/5=

$10we have x=$100, c=10, d=5, and our right answer should give you $10 after putting values of x,c and d.

E gives $10 as answer.

SO E is the correct answer.

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It’s not that I’m so smart, it’s just that I stay with problems longer. -- Albert Einstein