. A telephone switchboard 100-pair cable can be made up either enameled wire or tinned wire. There will be 400 soldered connections. The cost of soldering a connection on the enameled wire will be P1.65, on the tinned wire it will be P1.15. A 100-pair cable made up with enameled wire cost P0.22 per linear foot and those made up of tinned wire cost P0.75 per linear foot. Determine the length of cable run in feet so that the cost of each installation would be the same.