Milanputs 1 4 ŽĨŚĞƌůĂǁŶͲŵŽǁŝŶŐŵŽŶĞLJŝŶƐĂǀŝŶŐƐĂŶĚƵƐĞƐ 1 2of the remaining money to pay back her sister. If she has $15 left, how much did she have at first?