In an arithmetic series, if the sum of third and seventh terms is 8 and sum of the sixth and tenth terms is 26, then what is the first term of the sequence?
Sum of first 13 terms of an arithmetic progression is 312. What is the sum of the first 14 terms, if the first term and the common difference are positive integers?
An arithmetic sequence formed of 11 terms, and the sum of all its terms equals to 220. Find the middle term in that sequence.
For an Arithmetic Progression (AP), the sum of first four terms and first eight terms is 288. If the sum of first twelve terms is 480, then what is the sum of first 15 terms of this AP?
