InterviewSolution
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InterviewSolution
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If `a ,b ,a n dc`are in A.P. `p ,q ,a n dr`are in H.P., and `a p ,b q ,a n dc r`are in G.P., then `p/r+r/p`is equal to`a/c-c/a`b. `a/c+c/a`c. `b/q+q/b`d. `b/q-q/b`A. `a/c-c/a`B. `a/c+c/a`C. `b/q+q/b`D. `b/q-q/b` |
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Answer» Correct Answer - B `p/r+r/p=(p^(2)+r^(2))/(pr)=((p+r)^(2)-2pr)/(pr)` `=((4p^(2)r^(2))/q^(2)-2pr)/(pr)[{:(because" p,q,r are in H.P."),(" "thereforeq=(2pr)/(p+r)):}]` `=(4pr)/q^(2)-2=(4b^(2))/(ac)-2` `[because` ap,bq,cr are in A.P. `rArrb^(2)q^(2)=acpr]` `=((a+c)^(2))/(ac)-2[a,b,c` are in A.P`rArr2b=a+c]` `=a/c+c/a` |
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