Question

Find sum of '10' terms of an A.P. whose first term is 3 and the common difference is 6. *​

Answer 1

Answer:

300

Step-by-step explanation:

Given,

First term of an A.P(a) = 3

Common difference(d) = 6

To Find :-

Sum of first '10' terms of an A.P

How To Do :-

As they gave the value of First term(a) and common difference(d) we need to substitute these values in formula of Sum of 'n' terms of an A.P . Here we need to consider 'n' = 10 because they asked to find the sum of '10' terms of an A.P

Formula Required :-

Sum of 'n' terms of an A.P :-

$S_n=\dfrac{n}{2}[2a+(n-1)d]$

Solution :-

Taking 'n' = 10

Substituting in the formula :-

$S_{10}=\dfrac{10}{2}[2(3)+(10-1)6]$

$=5[6+(9)6]$

= 5[6 + 54]

= 5[60]

= 300

∴ Sum of 10 terms of an A.P = 300