I am currently working on a project in which two small computer fans are powered from a USB port. I want to be able to get two laptop fans powered off of one USB slot.
I was looking into some solutions, and I found a power cord that matches exactly what I want to do. The thing I am confused is that when the power cable is split, the cables 
double at the point it splits, which is also the point in which I want to solder to the USB wire.
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The problem I face is that the USB only has 4 single free cables , not two cables on top of each other in each pin slot like where the Y split Molex cable above, so I can confused as to how I would attach it to the USB if there is one more cable on all slots? Are the cables attached at the end by one of those Molex pins, and then I just solder the pins to the exposed USB wire?
Furthermore, there are two black wires in seperate pins on the Split Molex cable, which one would I solder to the USB, as I know the only red cable would be soldered to the only red cable on the usb.
In comments: How would I solder the Molex connector to a USB if the molex connector has 2 wires seperated into 4 sections (as the USB cable only has one wire separated into 4 sections). If you look at my last picture, would I just solder those metal pins directly to the exposed wire on the usb, or would I chop those pins off, solder the two wires on the molex together, then solder the now combined wires to the usb wire?