Question

2+4+6+8+.. sum of first 12 even positive
natural integers is​

Answer 1

GiveN :-

• First term = 2

• Common difference = 2

• Number of terms = 12

To FinD :-

• Sum of first 12 even positive integers

SolutioN :-

★ By using Sₙ formula :

$\longrightarrow \boxed{\green{\bf S_n = \frac{n}{2} \bigg[2a + (n - 1)d \bigg]}} \\ \\\longrightarrow \sf S_n = \frac{12}{2} \bigg[2 \times 2 + (12 - 1)2 \bigg] \\ \\\longrightarrow \sf S_n = 6 \: [ \: 4 + 22 \: ] \\ \\\longrightarrow \sf S_n = 6 \times 26 \\ \\ \longrightarrow \underline{\boxed{\blue{\sf S_n = 156}}}$

Answer 2

Answer:

156

Step-by-step explanation:

You can use Arithmetic Progression. (AP)

(Total numbers)/2 × (first number + last number)

= (12/2) × (2 + 24)

= 6 × 26

= 156

This formula can only be used when the numbers we have to add have the same difference.