A skilled barista carefully controls the water temperature for brewing to maximize the flavor of coffee. Using a precise heater, he heats a fixed amount of water and records the relationship between the heat added Q and the water temperature T on a graph.
The graph shows a straight line (linear function) with the horizontal axis representing the heat added Q [J] and the vertical axis representing the water temperature T [∘C]. According to the record, the temperature just before heating began (Q=0 [J]) was Tstart, and after adding a total heat Qtotal, the temperature reached the ideal brewing temperature Tend.
Find the total heat Qtotal [J] supplied by the heater to the water. Evaporation of water during heating and heat loss to the surroundings can be neglected. The specific heat capacity of water is assumed to be constant regardless of temperature.
Give the value of Qtotal as a positive integer. Do not include the unit (J); provide the numerical value only.