waecmaths question:
The average age of a group of 25 girls is 10 years. If one girl aged 12 years and 4 months joins the group, find, correct to one decimal place, the new average age of the group.
Option A:
10.1 years
Option B:
9.3 years
Option C:
8.7 years
Option D:
8.3 years
waecmaths solution:
Total age of the 25 girls is 250 years
The girls age who was later added to the group is 12 years and 4 months, that is 12.33 years
Total ages of the girls = 250 + 12.33 = 262.33
The new average will be (262.33) ÷ 26 =10.1 to 1 decimal place
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