.
pen = pencil + 30, (1)
5 pens + 2 pencil = 430 (cents)
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5*(pencil+30) + 2 pencil = 430,
5*pencil + 150 + 2 pencil = 430,
7 pencil = 430 - 150,
7 pencil = 280 ====> pencil =
= 40 cents.
Answer. Pencil costs 40 cents. Pen costs 40 + 30 = 70 cents.
Solved.