At night special lights must be installed in the main buildings of an elementary school. The lights were turned on and off from the school security guard post. The diagram on the left shows the layout of the school. The symbols I, II, III, IV, V, and VI are used for grades 1 to 6, KK for small rooms, P for library, G for teacher's room, K for canteen, and S for security guard post. The table on the right shows the length of the power cord in meters between each lamp installed.

(a) Draw a graph that models the problem.

(b) How to connect the lamps to each other using the minimum length of power cord? What is the minimum length of cable required? (In your answer to this question, please describe the approach/method you used).

 

KK S50. K d VI 00001 V IV E " P . 60655560 . - K - . =25. 45 . 25 11 . 45 . III . 20 . - d G - 47 20 . IV . . 45 . . . . 09 40 . 8.40 . 090609 40 . . . . . 55 . . . . . . . . 90 . . 5590 . 45 . 63 - . . . . . > . . " 85 . - 50 S