What is the sum of the number of girls in school C, the number of girls in school E and the number of boys in school D together?

Answer: Option D

$$\begin{array}{rl}& \text{Number of students in:}\\ & \text{A → }\frac{12}{100}\times 6000=720\\ & \text{B → }\frac{9}{100}\times 6000=540\\ & \text{C → }\frac{26}{100}\times 6000=1560\\ & \text{D → }\frac{18}{100}\times 6000=1080\\ & \text{E → }\frac{29}{100}\times 6000=1740\\ & \text{F → }\frac{6}{100}\times 6000=360\end{array}$$

Number of boys in:
A → 500
B → 400
C → 900
D → 600
E → 1200
F → 100

Number of girls in:
A → 720 - 500 = 220
B → 540 - 400 = 140
C → 1560 - 900 = 660
D → 1080 - 600 = 480
E → 1740 - 1200 = 540
F → 360 - 100 = 260

Required sum
= 660 + 540 + 600
= 1800