6 boys have a mean age of 10 years and 14 girls have a mean age of 5 work out the mean age of the 20

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6 boys have a mean age of 10 years and 14 girls have a mean age of 5 work out the mean age of the 20 children

Calculate Sum of boys ages:
Sum of boys ages/6 = 10
Cross multiply, and we get:
Sum of boys ages = 6 * 10
Sum of boys ages = 60

Calculate Sum of girls ages:
Sum of girls ages/14 = 5
Cross multiply, and we get:
Sum of girls ages = 14 * 5
Sum of girls ages = 70

Average of 20 children is:
Average of 20 children = (Sum of boys ages + sum of girls ages)/20
Average of 20 children = (60 + 70)/20
Average of 20 children = 130/20
Average of 20 children = 6.5 years