Question

D
Questos
11. (a) What is 1+ 2+ 3+ ... + 50 ?
(b) What is 2 + 4+ 6+ ... + 100 ?
(c) What is 3+ 5+ 7+ ... + 101 ?​

Answer 1

Answer:

1.an = 50

a = 1

d = 1

n = 50

s50 = 25(2+49×1)

25×(2+49)

25×51

s50 = 1275

2.an =100 d = 2

n = 50

s50 = 25(4+49×2)

25×(4+98)

25×102

s50= 2550

3.an = 101

a = 3

n = 50

s50 = 25×(6+49×2)

25×(6+98)

25×104

2600