Question 19
In the diagram below, the figure is divided into seven regions labelled A, B, C, D, E, F and G. Ros wants to fill in the diagram below with the positive integers from 1 to 7 in each region, where each integer can be only used exactly once.
If A + G + D = B + G + E = C + G + F, in how many ways can Ros complete the diagram?
If A + G + D = B + G + E = C + G + F, in how many ways can Ros complete the diagram?