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In a geometric progression, the fourth term exceeds the third term by $$24$$ and the sum of the second and third term is $$6$$. Then, the sum of the second, third and fourth terms is ------.
Correct Answer: 35.1
We can write the terms as $$6-a_3,a_3,a_3 +24$$
Since the terms are in GP, $$a_3^2 = a_4a_2$$
$$a_3^2 = (6-a_3)(a_3+24)$$
$$a_3^2 = (6-a_3)(a_3+24)$$
$$ 2a_3^2+18a_3-144 = 0$$
$$a_3^2+9a_3-72=0$$
Solving using the quadratic formula we get
$$ a_3 = \dfrac{-9\pm \sqrt{81+288}}{2} =Β \dfrac{-9\pm\sqrt{ 369}}{2}$$
$$a_3 = 5.1 \text{ or } -14.1$$
Thus, sum of the terms isΒ
$$a_3 + 30 = 35.1 \text{ or } 15.9$$
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