Question

find the sum of 30 terms of a.p 5+10+15+...​

Answer 1

Answer:

$\huge\longrightarrow$ Solution ::

Step-by-step explanation:

$sn = \frac{n}{2} (2a + (n - 1)d$

$s30 = \frac{30}{2} (2(5) + (30 - 1)5$

$s30 = 15(10 + 145)$

$s30 = 15(155) = 2325$

Answer 2

Answer:

a = 5

n = 30

d = 10 - 5 = 5

$sn \: = \frac{n}{2} (2a \: + |n - 1| d) \\ \\ = \frac{30}{2} (2 \times 5 + |30 - 1| \times 5 ) \\ \\ = 15(10 + 29 \times 5) \\ \\ = 15(10 + 145) \\ \\ = 15(155) \\ \\ = 2325$

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