Question

find the sum of first 20 even mumbers​

Answer 1

Answer:

420

Step-by-step explanation:

2+4+6+8+10+12+14+16+18+20+22....

Answer 2

AP: 2, 4, 6...40

Here: first term, a = 2

last term, t = 40

number of terms, n = 20

Apply the formula:

$\rm S_{n} = \frac{n}{2} × ( a + t)$

$\rm S_{20} = \frac{20}{2} × ( 2 + 40 )$

$\rm S_{20} = 10 × 42$

$\rm S_{20} = 420$