A prelimary investigation reveals that an unknown material has a melting range around 250 C. The heating curves for a melting point apparatus are...

A prelimary investigation reveals that an unknown material has a melting range around 250 °C. The heating curves for a melting point apparatus are shown below. Use the curves to determine what voltage would be required to produce a temperature change of 2 °C/min close to the needed melting point.

What voltage must the melting point apparatus be run at in order to produce a 2 °C/min change near 250°C? Enter the votage to the nearest 5 volts.