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Question
In an AP,t6=2(t3)+1 and t4+t5=5(t2). The 9th term of the AP is:
In an AP,t6=2(t3)+1 and t4+t5=5(t2). The 9th term of the AP is:
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Solution
The correct option is D 26
We know that in AP nth term( tn)= a + (n - 1)d
Given,
t6=2(t3)+1
a+5d=2(a+2d)+1
a−d=−1−−−−−−−−−(1)
t4+t5=5(t2)
a+3d+a+4d=5(a+d)
3a−2d=0−−−−−−−(2)
(2) - 2 x (1)
a = 2
From equation (1), a - d = -1
d = 3.
9thterm=a+8d
= 2 + 8 × 3
= 26
We know that in AP nth term( tn)= a + (n - 1)d
Given,
t6=2(t3)+1
a+5d=2(a+2d)+1
a−d=−1−−−−−−−−−(1)
t4+t5=5(t2)
a+3d+a+4d=5(a+d)
3a−2d=0−−−−−−−(2)
(2) - 2 x (1)
a = 2
From equation (1), a - d = -1
d = 3.
9thterm=a+8d
= 2 + 8 × 3
= 26
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