A) (4/7, 3/7)
B) (2, 3/8)
C) (3/2, 1/2)
D) (3, 1/4)
E) (4, 3/4)
Correct Answer: D
Solution :
According to question \[\frac{a}{1-r}=4\] ???.. (i) and \[ar=\frac{3}{4}\] ?? (ii) From Eq. (i), \[a=4(1-r)\] On putting this value of a in Eq. (ii), we get \[4(1-r)r=\frac{3}{4}\] \[\Rightarrow \] \[16r-16{{r}^{2}}=3\] \[\Rightarrow \] \[16{{r}^{2}}-16r+3=0\] \[\Rightarrow \] \[16{{r}^{2}}-12r-4r+3=0\] \[\Rightarrow \] \[4r(4r-3)-1(4r-3)=0\] \[\Rightarrow \] \[r=\frac{1}{4},\frac{3}{4}\] If\[r=\frac{1}{4},\]then\[a=3\] \[\therefore \]One of the pair of values of (a, r) is\[\left( 3,\frac{1}{4} \right)\].
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