Step 1 :Let P be the number of purple counters, T be the number of triangular counters, and S be the number of square counters. We have the following equations:
Step 2 :\(0.7P = 0.6T\)
Step 3 :\(0.4T = 14\)
Step 4 :Solve the second equation for T: \(T = \frac{14}{0.4} = 35\)
Step 5 :Substitute T into the first equation: \(0.7P = 0.6(35)\)
Step 6 :Solve for P: \(P = \frac{0.6(35)}{0.7} = 30\)
Step 7 :Since there are 14 red triangles, there are \(35 - 14 = 21\) purple triangles.
Step 8 :Since 70% of the purple counters are triangles, there are \(30 - 21 = 9\) purple squares.
Step 9 :\(\boxed{9}\) square counters in the bag.