SSC Sample Paper Mock Test-2 SSC CGL Tear-II Paper-1

  • question_answer
    If \[a,\]\[b,\]\[c,\]\[d\]and \[e\] are in continued proportion, then \[a/e\] equal to

    A)  \[{{a}^{3}}/{{b}^{3}}\]                   

    B)  \[{{a}^{4}}/{{b}^{4}}\]

    C)  \[{{b}^{3}}/{{a}^{3}}\]                   

    D)  \[{{b}^{4}}/{{a}^{4}}\]

    Correct Answer: B

    Solution :

    Since, a b, c, d and e are in continued proportion.
    \[\therefore \]      \[\frac{a}{b}=\frac{b}{c}=\frac{c}{d}=\frac{d}{e}\]
    \[\Rightarrow \]   \[\frac{e}{d}=\frac{d}{c}=\frac{c}{b}=\frac{b}{a}\]
    \[\therefore \] \[c=\frac{{{b}^{2}}}{a}\] \[\left( \because \frac{c}{b}=\frac{b}{a} \right)\]
    \[\therefore \]\[d=\frac{{{c}^{2}}}{b}=\frac{{{b}^{4}}}{{{a}^{2}}}\cdot \frac{1}{b}=\frac{{{b}^{3}}}{{{a}^{2}}}\]
    \[\therefore \]\[e=\frac{{{d}^{2}}}{c}=\frac{{{b}^{6}}}{{{a}^{4}}}\cdot \frac{a}{{{b}^{2}}}=\frac{{{b}^{4}}}{{{a}^{3}}}\]
    \[\therefore \]\[\frac{a}{e}=\frac{a}{({{b}^{4}}/{{a}^{3}})}=\frac{{{a}^{4}}}{{{b}^{4}}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner