Question

A can do a work in 15 days and B in 20 days. If both work together for 4 days then what fraction of the work is left?

Answer 1

Answer:

3 by 10 are left.

Step-by-step explanation:

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Answer 2

Given

• A can do a work in 15 days and B in 20 days
• If both work together for 4 days

Explanation

One Day Work of A = ${\sf{ \left( \dfrac{1}{15} \right) }}$

One Day Work of B = ${\sf{ \left( \dfrac{1}{20} \right) }}$

we have to find the time taken together by A and B as:-

$\colon\implies{\sf{ \left( \dfrac{1}{15} + \dfrac{1}{20} \right) }} \\ \\ \\ \colon\implies{\sf{ \left( \dfrac{4+3}{60} \right) }} \\ \\ \\ \colon\implies{\sf{ \left( \dfrac{7}{60} \right) }}$

Now, We can find the work done by A and B in 4 Days as Follows:-

$\colon\mapsto{\sf{ \dfrac{7}{ \cancel{60} } \times \cancel{4} }} \\ \\ \colon\mapsto{\sf{ \dfrac{7}{ 15 } }}$

Since, We also find that how much work left to be done :-

$\colon\mapsto{\sf{ 1- \dfrac{7}{ 15 } }} \\ \\ \colon\mapsto{\sf{ \dfrac{15-7}{ 15 } }} \\ \\ \colon\mapsto{\sf\green{ \dfrac{8}{ 15 } }}$

Hence,

${\underline{\sf{ The \ work \ that \ left \ is \ \dfrac{8}{15} . }}}$