Question

Sn = 50
a = 5 d =1÷4
find n = ?​

Answer 1

Answer:

sn=n/2[2a+(n-1)d]

50=n/2[2×5+(n-1)4]

50=n/2[10+(n-1)4]

50(n-1)×4=n/2×10

50(n-1)×4=n×5

50/5=(n-1)×4

(n-1)×4=10