The 4th and 7th term of an arithmetic progression are 11 and -4 respectively. What is the 15th term?
A. -49
B. -44
C. -39
D. -34
Answer: Option B
Solution(By Examveda Team)
Let the first term of an AP = a and the common difference = d4th term of AP = A4 = a + 3d =11 ......(1)
7th term = A7 = a + 6d = -4 ......(2)
Subtracting equation (1) from (2), we get :
⇒ 6d - 3d = -4 -11
⇒ 3d = -15
⇒ d = $$\frac{{ - 15}}{3}$$ = -5
Substituting it in equation (1)
⇒ a = 11 - 3(-5) = 11 + 15 = 26
∴ 15th term = A15 = a + 14d
= 26 + 14(-5)
= 26 - 70
= -44
Related Questions on Progressions
Find the first term of an AP whose 8th and 12th terms are respectively 39 and 59.
A. 5
B. 6
C. 4
D. 3
E. 7
The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is
A. 600
B. 765
C. 640
D. 680
E. 690
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