Questions

A - A - A = 20
B - B - B = 15
C - C - C = 25

A = -20
B = -15
C = -25

=> A + B + C = (-20)+(-15)+(-25) = -20 - 15 - 25 = -60.

Fractional distillation is the process of seperation of a mixture of two or more liquids into the different fractions, which differ fairly widely in their boiling points. The liquid with a lower boiling point will be vaporized first and hence would be the distillate (first fraction). Eg. Ethyl alcohol has a boiling point of 78.10C and water 1000C. When a mixture of these two liquids is heated, alcohol vaporizes first and is collected separately as the distillate. 

In each circle, starting at the  top left segment ,numbers increase, as you move clockwise,by 2 for the upper left circle,3 for the upper right, 4 for the lower right and 5 for the lower left