1003085209

SubArea: 
Arithmetic sequences
Level: 
B
Project ID: 
1003085209
Accepted: 
1
Clonable: 
0
Easy: 
0
The sum of the $2$nd and the $4$th term of an arithmetic sequence is $1.2$, the sum of the first $10$ terms is $3.5$. Find the first term.
$0.8$
$0.3$
$0.35$
$-0.1$
$-0.5$