Question 1109274
{{{5N+10D+25Q=440}}} <-- Total value of coins 
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{{{Q=2N}}} <--- Twice as many Q as N
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{{{D=5+N}}}<--- Five more D than N
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Substituting into the first equation,
{{{5N+10(5+N)+25(2N)=440}}}
{{{5N+50+10N+50N=440}}}
{{{65N=390}}}
Solve for N.
Then use the other equations to solve for D and Q.