Permutation and Combination -04

Explanation:-

$$\eqalign{ & {\text{Let}}\,{\text{T}}{\text{.D}}{\text{.}}\,{\text{be}}\,{\text{Re}}{\text{.}}\,{\text{1}}{\text{.}} \cr & {\text{Then,}}\,{\text{B}}{\text{.D}}. = Rs.\,\frac{{11}}{{10}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,1.10. \cr & \therefore {\text{Sum}} = Rs.\,\left( {\frac{{1.10 \times 1}}{{1.10 - 1}}} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,\left( {\frac{{110}}{{10}}} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,11. \cr & \therefore {\text{S}}{\text{.I}}{\text{.}}\,{\text{on}}\,{\text{Rs}}{\text{.}}\,{\text{11}}\,{\text{for}}\,{\text{2}}\,{\text{years}}\,{\text{is}}\,{\text{Rs}}{\text{.}}\,{\text{1}}{\text{.10}} \cr & \therefore {\text{Rate}} = \left( {\frac{{100 \times 1.10}}{{11 \times 2}}} \right)\% \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 5\% \, \cr}$$

Explanation:-

$$\eqalign{ & {\text{P}}{\text{.W}}{\text{.}} = Rs.\,\left( {540 - 90} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,450. \cr & \therefore {\text{S}}{\text{.I}}{\text{.}}\,{\text{on}}\,Rs.\,450 = Rs.\,90. \cr & {\text{S}}{\text{.I}}{\text{.}}\,{\text{on}}\,Rs.\,540 \cr & = Rs.\,\left( {\frac{{90}}{{450}} \times 540} \right) \cr & = Rs.\,108 \cr & \therefore {\text{B}}{\text{.D}}. = Rs.\,108. \cr}$$

Explanation:-

$$\eqalign{ & T.D. = \sqrt {P.W. \times B.G.} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = \sqrt {576 \times 16} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = 96 \cr}$$

Explanation:-

$$\eqalign{ & {\text{Let,B}}{\text{.D}}{\text{.}} = \operatorname{Re} .\,1. \cr & {\text{Then,}}\,{\text{B}}{\text{.G}}{\text{.}} = \operatorname{Re} .\,\frac{3}{{25}}. \cr & \therefore {\text{T}}{\text{.D}}{\text{. = }}\left( {{\text{B}}{\text{.D}}{\text{. - B}}{\text{.G}}{\text{.}}} \right) \cr & = \operatorname{Re} .\,\left( {1 - \frac{3}{{25}}} \right) \cr & = \operatorname{Re} .\,\frac{{22}}{{25}}. \cr & {\text{Sum}} = \left( {\frac{{1 \times \left( {22/25} \right)}}{{1 - \left( {22/25} \right)}}} \right) \cr & = Rs.\,\frac{{22}}{3}. \cr & {\text{S}}{\text{.I}}{\text{.}}\,{\text{on}}\,Rs.\,\frac{{22}}{3}\,for\,1\frac{1}{2}{\text{years}}\,{\text{is}}\,\operatorname{Re} .\,1. \cr & \therefore {\text{Rate}} = \left( {\frac{{100 \times 1}}{{\frac{{22}}{3} \times \frac{3}{2}}}} \right)\% \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{{100}}{{11}}\% \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 9\frac{1}{{11}}\% \cr}$$

Explanation:-

$$\eqalign{ & B.G. = \frac{{{{\left( {T.D.} \right)}^2}}}{{P.W.}} \cr & = Rs.\,\left( {\frac{{36 \times 36}}{{800}}} \right) \cr & = Rs.\,1.62. \cr & \therefore B.D. = \left( {T.D. + B.G.} \right) \cr & = Rs.\,\left( {36 + 1.62} \right) \cr & = Rs.\,37.62 \cr}$$

Explanation:-

$$\eqalign{ & B.G. = \frac{{{{\left( {T.D.} \right)}^2}}}{{P.W.}} \cr & = Rs.\,\left( {\frac{{160 \times 160}}{{1600}}} \right) \cr & = Rs.\,16. \cr}$$

Explanation:-

$$\eqalign{ & \frac{{B.D. \times T.D.}}{{B.D. - T.D.}} \cr & = Rs.\,\left( {\frac{{72 \times 60}}{{72 - 60}}} \right) \cr & = Rs.\,\left( {\frac{{72 \times 60}}{{12}}} \right) \cr & = Rs.\,360. \cr}$$

Explanation:-

$$\eqalign{ & T.D. = \left( {\frac{{B.G. \times 100}}{{R \times T}}} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,\left( {\frac{{270 \times 100}}{{12 \times 3}}} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,750. \cr & \therefore B.D. = Rs.\left( {750 + 270} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,1020. \cr}$$

Explanation:-

$$\eqalign{ & T.D. = \left( {\frac{{B.G. \times 100}}{{Rate \times Time}}} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,\left( {\frac{{24 \times 100}}{{10 \times 2}}} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,120. \cr & \therefore P.W. = \frac{{100 \times T.D.}}{{Rate \times Time}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,\left( {\frac{{100 \times 120}}{{10 \times 2}}} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = Rs.\,600. \cr}$$

Explanation:-

$$\eqalign{ & {\text{S}}{\text{.I}}{\text{.}}\,{\text{on}}\,{\text{Rs}}{\text{.}}\,{\text{1600 = T}}{\text{.D}}{\text{.}}\,{\text{on}}\,{\text{Rs}}{\text{.}}\,{\text{1680}}{\text{.}} \cr & \therefore {\text{Rs}}{\text{.}}\,{\text{1600}}\,{\text{is}}\,{\text{the}}\,{\text{P}}{\text{.W}}{\text{.}}\,{\text{of}}\,{\text{Rs}}{\text{.}}\,{\text{1680,}}\,{\text{i}}{\text{.e}}{\text{.,}} \cr & {\text{Rs}}{\text{.}}\,{\text{80}}\,{\text{is}}\,{\text{on}}\,{\text{Rs}}{\text{.}}\,{\text{1600}}\,{\text{at}}\,{\text{15}}\% . \cr & \therefore {\text{Time}} = \left( {\frac{{100 \times 80}}{{1600 \times 15}}} \right){\text{year}} \cr & = \frac{1}{3}{\text{year}} = 4\,{\text{months}}{\text{.}} \cr}$$