Question

if the sum of the first 14 term of an ap is 2050 and its first term is 10 find the 20th term

Answer 1

$sum = \\ \frac{n}{2} (2a + (n - 1)d) = sum \\ \: n = 14 \\ a = 10 \\ sum = 2050 \\ putting \: values \\ 7(20 + 13d) = 2050 \\ 13d = \frac{2050}{7} - 20 \\ 13d = \frac{1910}{7} \\ d = \frac{1910}{91} \\ 20th \: term \\ = 10 + 19 \times \frac{1910}{91} \\ = \frac{37200}{91}$