To solve this we just need to understand that when A=1, B=7. So when the side for a is 7 that is basically multiplying A by 7 so we have to do the same to the B side. So when the B side is multiplied by 7 it would be 7*7 =49 so the ? is equal to 49 when that similar side is equal to 7.
This is all based on the fact that the two triangles must be similar triangles.
Each team needs two people for a 3-legged race. Therefore, the number of orders (combinations) of 2 people at a time from 8 is ₈C₂ = 8!/(2!6!) = (8*7*6!)/(2*6!) = (8*7)/2 = 56/2 = 28
