Question

Fourth term of an arithmetic progression is 11. What is the sum of the first 7 terms of the arithmetic progression

Answer 1

Answer:

Step-by-step explanation:

FOURTH TERM OF AP IS 7

THEN Tn=a+(n-1)d

THEN T4=a+(4-1)d

T4=a+3d

7=a+3d

Sn=n(2a+(n-1)d)/2

S7=7 (2a+(7-1)d)/2

S7=7 (2a+6d)/2

S7=7 (a+a+3d+3d)/2

S7=7 (a+3d+a+3d)/2

S7=7 (7+7)/2

S7=7 (14)/2

S7=98/2

S7=49 (ans)