Answer:
6,375
Step-by-step explanation:
[tex] t_{20} = a + (n - 1)d[/tex]
where a = first term = 5 and d = common difference.
[tex] t_{20} = 100 = 5 + (20 - 1)d [/tex]
100 = 5 + 19d
19d = 100 - 5 = 95
d = 95/19 = 5
d = 5
[tex] s_{n} = \frac{n}{2}(2a + (n - 1)d)) [/tex]
Sum of the first fifty terms =
[tex] s_{50} = \frac{50}{2}(2 \times 5 + (50 - 1)5)) = 25(10 + (49)5)) [/tex]
= 25 (10+245) = 25 (255) = 6,375
