Let S be the number of systems Rodney sold on the first street.
He sold 2S systems on the second street.
Based on his commission, he sold 175 / 25 = <<175/25=7>>7 systems.
In all, he sold S + 2S + 0 + 1 = 3S + 1 = 7 systems.
On the first and second streets, he sold 3S = 7 - 1 = 6 systems.
Thus, on the first street he sold S = 6 / 3 = <<6/3=2>>2 systems.
On the second street, Rodney sold 2 * 2 = <<2*2=4>>4 security systems.
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