The sixth term of an arithmetic progression is 23 and the sum of the first ten terms is 200. Find the seventh term.
Solution
Let the first term be \(a\) and the common difference be \(d\).
The sixth term is given by \(a + 5d = 23\).
The sum of the first ten terms is given by \(\frac{10}{2} (2a + 9d) = 200\), simplifying to \(5(2a + 9d) = 200\).
Solving the equations:
1. \(a + 5d = 23\)
2. \(5(2a + 9d) = 200\) simplifies to \(2a + 9d = 40\).
From equation 1, \(a = 23 - 5d\).
Substitute \(a = 23 - 5d\) into equation 2:
\(2(23 - 5d) + 9d = 40\)
\(46 - 10d + 9d = 40\)
\(46 - d = 40\)
\(d = 6\)
Substitute \(d = 6\) back into \(a = 23 - 5d\):
\(a = 23 - 5(6)\)
\(a = 23 - 30\)
\(a = -7\)
The seventh term is \(a + 6d = -7 + 6(6) = -7 + 36 = 29\).
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