Answer:
the increase resulting from this merger = 256
Explanation:
before the merger, both Fiat and Case's contribution to Herfindahl-Hirschman index = 16² + 8² = 320
after the merger, Fiat and Case's contribution to Herfindahl-Hirschman index = 24² = 576
the increase resulting from this merger = 576 - 320 = 256