Answer:
Socko gained 3/5 kg from month 1 to month 2.
Explanation:
Socko mass was 3/10 kg in month 1 and 9/10 kg in month 2.
The amount of mass he gained is k.
3/10 + k = 9/10
Subtract 3/10 from both sides.
k = 6/10
Reduce the fraction.
k = 3/5
Answer: Socko gained 3/5 kg from month 1 to month 2.