Assumed mean A = 150ClassFrequency100–1206120–14010140–16014160–18012180–2008A150B147.6C152D152.4 Step-by-Step Solutiond=x−150:−40,−20,0,20,40.∑fd=−240−200+0+240+320=120,N=50; mean =150+50120=152.4.Answer: D) 152.4