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Find four consecutive terms in an A.P. whose sum is 36 and the product of the 2nd and 4th is 105. The terms are in ascending order.. |
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Answer» let the 4 terms be a - 3d, a-d, a+d and a+3d Sum = 4a = 36, so a = 9 Product of 2nd and 4th = (9-d)(9+3d)=105 81+27d-9d-3d2 = 105 3d2-18d+24=0 d2-6d+8=0 (d-2)(d-4)=0 so d=2, or 4 numbers are 3, 7, 11, 15 or -3, 5, 13, 21 |
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