The 3rd and 7th term of an arithmetic progression are -9 and 11 respectively. What is the 15th term?
A. 28
B. 87
C. 51
D. 17
Answer: Option C
Solution(By Examveda Team)
$$\eqalign{ & {T_3} = a + 2d = - 9\,.....\,\left( 1 \right) \cr & {T_7} = a + 6d = 11\,.....\,\left( 2 \right) \cr & {\text{on solving}}\left( 1 \right)\,{\text{and}}\,\left( 2 \right) \cr & d = 5\,\& \,a = - 19 \cr & {T_{15}} = a + 14d \cr & \,\,\,\,\,\,\,\,\,\, = - 19 + 14\left( 5 \right) \cr & \,\,\,\,\,\,\,\,\,\, = 51 \cr} $$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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