Question

the averge of 3 sisters is 15, 2 sister age is 12 and 15 year.what is age is third sister?​

Answer 1

Answer:

18

Step-by-step explanation:

let X be the age of third sister.

since,

Avg=15

(12+15+X)/3=15

27+X=45

X=18

Age of third sister=18 year