Question

5. The average age of 3 sisters is 15. If the ages of 2
sisters are 12 years and 15 years, the age of the third
sister is
17 ore​

Answer 1

Answer:

18 years

Step-by-step explanation:

let the age of third sister be x

average of the ages of three sisters is 15

age of two sisters are 12 and 15

$\frac{x + 12 + 15}{3} = 15 \\ x + 12 + 15 = 15 \times 3 \\ x + 27 = 45 \\ x = 45 - 27 \\ x = 18$

therefore the age of third sister = 18 years

Hope you get your answer