Anita has two sisters and three brothers. The mean of all their ages is 6 years. What will their mean age be 10 years from now? What will their mean age be 20 years from now?

Answer: Now: 6 yr mean age in 10 yrs? 16 yr mean age in 20 yrs? 26 yr mean age
Why? Because regardless of the relationship between each sibling's age, your always adding the 10yrs to each individual, which you are then dividing out to determine the mean age. See proof below:
Including anita, there are 6 people. We'll define each age as an unknown variable. Assume we know nothing about the relationships between their ages
for example sake anita's age = a sister 1's age = b sister 2's age = c brother 1's age = d brother 2's age = e brother 3's age = f
Now: mean age = (a + b + c + d + e + f)/(6 people) = 6 yrs
in 10 yrs: mean age = ((a+10) + (b+10) + (c+10) + (d+10) + (e+10) + (f+10))/(6 people) mean age = (a + b + c + d + e + f + 60)/(6 people) mean age = (a + b + c + d + e + f)/(6 people) + (60)/(6 people) mean age = (a + b + c + d + e + f)/(6 people) + 10
Notice the first term is the same expression of the mean age for "Now" Thus, in 10 yrs: mean age = 6 + 10 = 16 yrs
The same principle applies for "x" yrs from now, as long as we know what the mean age is "Now"

Answered by Anonymous | 2024-06-10

10 years from now= 16
20 years = 26 ;

Answered by jacksonstrand4 | 2024-06-12

The mean age of Anita and her siblings will be 16 years in 10 years and 26 years in 20 years. This is calculated by adding the total expected age increases to their current total age. Therefore, their ages all increase consistently over time.
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Answered by Anonymous | 2024-10-16