Question

The arithmetic mean of X , X+3 ,X+6 , X+9 and X+12 is 10 than find x?​

Answer 1

1. (x+x+3+x+6+x+9+x+12)/5=10
2. (5x+30)/5=10
3. 5x+30=50
4. 5x=20
5. x=4