Multiple choice

The mean age of a group of persons is 40. Another group has mean age 48. If the ratio of number of persons in two groups is 5 : 3, then mean age of all the persons in two groups is

  1. $42$
  2. $43$
  3. $44$
  4. $45$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The combined mean is the weighted average of the two groups: ((5 * 40) + (3 * 48)) / (5 + 3) = (200 + 144) / 8 = 344 / 8 = 43.

AI explanation

Using the combined mean formula with the given ratio of 5 to 3, we can treat the number of people in the groups as 5 and 3. The total sum of ages is (5 * 40) + (3 * 48) = 200 + 144 = 344. The total number of people is 5 + 3 = 8. Dividing the total sum by the total number of people gives 344 / 8, which equals 43.