A alone can reap a certain field in 15 days and B in 12 days. If A begins alone and after a certain interval B joins him, the field is reaped in 7.5 days. How long did A and B work together.

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Satt Academy · Accepted Answer

প্রশ্নে বলা হচ্ছে, একটি জমির ধান কাটতে A একাকী 15 দিন এবং B একাকী 12 দিন সময় নেয়। যদি A একাকী ধান কাটা শুরু করে এবং কিছুদিন পর B তার সাথে যোগ দেয়, এরফলে মোট 7.5 দিনে তারা সম্পূর্ণ জমির ধান কাটতে পারলো। A এবং B একসাথে কতদিন কাজ করেছিল?

Let, B works for x days

In 1 day A can do $= \frac{1}{15} p a r t$

In 7.5 days A can do $= \frac{7.5}{15} = \frac{1}{2}$ part

In 1 day B can do $= \frac{1}{12}$ part

In x day B can do $= \frac{x}{12}$ part

According to the question, $\frac{1}{2} + \frac{x}{12} = 1$

$\Rightarrow \frac{6 + x}{12} = 1 \Rightarrow 6 + x = 12 ∴ x = 12 - 6 = 6 d a y s T h u s, A a n d B w o r k 6 d a y s t o g e t h e r .$

= 115 partIn 7.5 days A can do = 7.515 = 12 partIn 1 day B can do = 112 partIn x day B can do = x12 partAccording to the question, 12 + x12 = 1 ⇒ 6+x12 = 1

A alone can reap a certain field in 15 days and B in 12 days. If A begins alone and after a certain interval B joins him, the field is reaped in 7.5 days. How long did A and B work together.
(Work & Time)

Question:
A alone can reap a certain field in 15 days and B in 12 days. If A begins alone and after a certain interval B joins him, the field is reaped in 7.5 days. How long did A and B work together.
(Work & Time)

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Hi, আমি SATT AI!

A alone can reap a certain field in 15 days and B in 12 days. If A begins alone and after a certain interval B joins him, the field is reaped in 7.5 days. How long did A and B work together. (Work & Time)

Question: A alone can reap a certain field in 15 days and B in 12 days. If A begins alone and after a certain interval B joins him, the field is reaped in 7.5 days. How long did A and B work together. (Work & Time)

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Satt AI

Hi, আমি SATT AI!

A alone can reap a certain field in 15 days and B in 12 days. If A begins alone and after a certain interval B joins him, the field is reaped in 7.5 days. How long did A and B work together.
(Work & Time)

Question:
A alone can reap a certain field in 15 days and B in 12 days. If A begins alone and after a certain interval B joins him, the field is reaped in 7.5 days. How long did A and B work together.
(Work & Time)