Question

(b) 2 + 4 + 6 + ... + 100​

Answer 1

Answer:

2+4+6......100

25 ( 4 +48) = 25× 52 = 1300

Answer 2

A.P. = 2,4,6,8.........,100

a=2 , d = 2

L = a + (n-1)d

100 = 2 + (n - 1)2

98 = (n-1)2

98/2 = n - 1

49 = n-1

50= n

Sum of 50 terms

$\frac{50}{2} (2 \times 2 + (50 - 1)2) \\ = 25(4 + 49 \times 2) \\ = 25(4 + 98) \\ = 25 \times 102 \\ = 2550$