1 answer
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600 = 5 n + 10 d + 25 q
n = 10
d + q = 25
600 = 50 + 10 d + 25 q
or
550 = 10 d + 25 q
or
110 = 2 d + 5 q
so
2 d + 5 q = 110
2 d + 2 q = 50
----------------
3 q = 60
q = 20
you take it from there.