Question

d=2/3,An=10,n=20,Sn=?,a=?​

Answer 1

Answer:

a=-8/3

Sn= 220/3

Step-by-step explanation:

d= 2/3

an= 10

n=20

sn=?

a=?

an= a + <n-1.d

10= a + 19<2/3>

a=10-19*2/3

a=-8/3

Sn= n/2<2a+ <n-1>d>

Sn= 10 *   [2*-8/3 + {19*2/3}]

Sn= 220/3

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Answer 2

Answer:

An = a+ (n-1)d

10 = a + (20 - 1)2/3

10 = a + 19×2/3

10 = a + 38/3

a = 10 - 38/3

a = (20-38)/3

a = (-18)/3

a = -6

Sn = n/2(a+L)

S20 = 20/2(-6+10)

S20 = 10(4)

S20 = 40