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The first term of two A.P.s are equal and the ratios of their common differences is 1:2 . if the 7th term of first A.P and 21st term of the second A.P are 23 and 125 respectively. find two A.P.S |
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Answer» LET the first term of first A.P. be a and COMMON DIFF. be d. Let the the first term of SECOND A.P. be a and common difference be 2d. 7th term =a+6d=23 a+40d=125 subtracting:- 34 d=102 d=102/34=3 a=5 first A.P.=5,8,11,14,17,20,23,...... second A.P=5,11,17,23,..... |
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