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5. Find five numbers in A.P. whose sum is 12and the ratio of the first to the last terms is2:3 |
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Answer» Sum of an AP is given by n/2 (2a+(n-1)d)Siince sum of first 5 terms is given∴ 5/2 (2a+4d)=12= a+2d=12/5 ___(1)and a/d=2/3 __(2)∴ put value of a from (2) in (1) we get 2d/3 +2d=12/5∴d=9/10 and a=2d/3=3/5=6/10therefore first five numbers are a ,a+d,a+2d,a+3d,a+4d6/10,15/10,24/10,33/10,42/10 |
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