Question

A can do peice of work in 25 days and B can finesh it in 20 days, both started together,after 5 days A left. In how many days will B finesh the remaining​

Answer 1

A n s w e r

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G i v e n

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• A can do piece of work in 25 days

• B can finish it in 20 days

• A & B worked together for 5 days after that A left

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S o l u t i o n

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$\underline{\bold{\texttt{One day work of A :}}}$

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A can finish the work in 25 days

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➜ $\sf \dfrac { 1 } { 25 }$

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$\underline{\bold{\texttt{One day work of B :}}}$

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B can finish the work in 20 days

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➜ $\sf \dfrac { 1 } { 20 }$

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$\underline{\bold{\texttt{One day work when A and B work together :}}}$

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➜ $\sf \dfrac { 1 } { 25 } + \dfrac { 1 } { 20 }$

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➜ $\sf \dfrac { 4 + 5 } { 100 }$

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➜ $\sf \dfrac { 9 } { 100 }$

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$\underline{\bold{\texttt{5 days work when A and B work together :}}}$

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A & B worked together for 5 days

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➜ $\sf \dfrac { 9 } { 100 } \times 5$

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➜ $\sf \dfrac { 9 } { 20 }$

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$\underline{\bold{\texttt{Remaining work after initial 5 days :}}}$

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➜ $\sf 1 - \dfrac { 9 } { 20 }$

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➜ $\sf \dfrac { 11 } { 20 }$

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Given that remaining work is completed by B alone

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• Let B complete the remaining work in "x" days

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So,

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➜ $\sf \dfrac { 1 } { 20 } \times x = \dfrac { 11 } { 20 }$

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➨ x = 11

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• Hence B will take 11 days to complete the remaining work alone

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$\underline{\bold{\texttt{Total days required to complete the work :}}}$

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Number of days A & B worked together + Number of days B work alone

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➜ 5 + 11

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➨ 16

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• Hence total days required to complete the work is 16