Concept:Harmonic mean for ungrouped data is given by H=∑xi​1​n​.Explanation:Given numbers: 5,6,10,15,20,24.Number of terms: n=6.Sum of reciprocals: 51​+61​+101​+151​+201​+241​.Find common denominator 120: 12024​+12020​+12012​+1208​+1206​+1205​=12075​=85​.Thus, H=85​6​=6×58​=548​=9.6.Answer:9.6