Answer :

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

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