Let M be the age of the mother.
The total age of the 7 children is 7 * 13 years 2 months = 91 years 14 months.
The total age of the mother and the 7 children is M + 91 years 14 months.
According to the second scenario, the total age of the mother and the 7 children is 8 * 17 years 7 months = 139 years 4 months.
Therefore, we can set up the equation:
M + 91 years 14 months = 139 years 4 months
M + 91 years + 14 months = 139 years + 4 months
M + 91 years = 139 years - 14 months
M = 48 years - 14 months
M = 47 years 10 months
Therefore, the age of the mother is 47 years 10 months.
A mother has 7 children. The mean age of the children is 13 years 2 months. If the mother's age is included, the mean age rises to 17 years 7 months.calculate the age of the mother
3 answers
Mean age of 7 children=sum of ages of 7 children/7
13 years 2 months=sum of 7 children/7
Sum of ages of 7 children=7×13 years 2 months
=91 years 14 months
=91 years+1 year 2 months
=92 years 2 months
Mean age of 7 children +1mother= sum of ages of 7 children+1 mother/8
17 years 7 months= sum of ages of 8 children/8
Sum of ages of 8 children=8×17 years 7 months
=136 years 56 months
=136 years+ 4 years 8 months
= 140 years 8 months
Therefore: age of mother= 140 years 8 months -92 years 2 months
= 48 years 6 months
13 years 2 months=sum of 7 children/7
Sum of ages of 7 children=7×13 years 2 months
=91 years 14 months
=91 years+1 year 2 months
=92 years 2 months
Mean age of 7 children +1mother= sum of ages of 7 children+1 mother/8
17 years 7 months= sum of ages of 8 children/8
Sum of ages of 8 children=8×17 years 7 months
=136 years 56 months
=136 years+ 4 years 8 months
= 140 years 8 months
Therefore: age of mother= 140 years 8 months -92 years 2 months
= 48 years 6 months
Apologies for my error in the calculation earlier. Your correction is correct. The age of the mother should indeed be 48 years 6 months. Thank you for pointing that out.
6 answers