Final answer:
The charges at the corners of an equilateral triangle have a positive charge at one corner and negative charges at the two remaining corners, with the positive and one negative charge having twice the magnitude of the other negative charge.
Step-by-step explanation:
According to the given information, the configuration of the charges in an equilateral triangle setup is such that electric-field lines emerge from charge 1, indicating it is positive, while they enter into charges 2 and 3, indicating these are negative. Furthermore, the charge ratio is given as 91:92:93 = +2:-1:-2, implicating that the magnitude of charges 1 and 3 is twice that of charge 2. Therefore, the correct configuration of the charges is a positive charge at one corner and negative charges at the other two corners, with the magnitudes of the positive and one of the negative charges being twice that of the other negative charge.