Answer:a,b and c.
Explanation:
E= Economics
S= Sociology
From statement 1,
E= 40
S= 30
E+S = 40+30
Thus, E+S = 70
Hence, option "a" is a possible combination.
From statement 1 also,
E/2 + S = (40/2) + 30 = 20+30=50
Hence option "b" is correct.
From statement 2,
E= 30
S = 50
E+S = 30+ 50 = 80
2E + S =(2×30) + 50 = 60+50=110
Thus, "c" is correct.
for option d
E+ S = 20 will be tested using statements 1 and 2 separately.
Using statement 1,
E+S = 30+40=70 which is not equal to 20. Hence option "d" is wrong.
Also, using statement 2,
E+S = 30+50= 80 which is not equal to 20. Hence option d fails to satisfy statement 2.
Hence the equations that describe possible combination of pages of Economics and Sociology are equations a, b, and c.