Question

At E °C, 30mL of coffee is forgotten in a thermos glass. If fresh coffee at F °C is added to the cooled coffee, the temperature of the coffee rises to G °C under room conditions. Calculate the amount of coffee added to the thermos. A two-digit number ending in 0 or 5, where E < G < F)

Answer 1

$c_1V_1(G-E)=c_2V_2(F-G),$

$c_1=c_2,$

$V_2=V_1\cdot \frac{G-E}{F-G}.$