Karim and Bablu can build a wooden table in 3 days. Bablu can do it alone in 5 days. How many days would it take Karim to do this job alone?
বিকল্পসমূহ (নিজের উত্তর যাচাই করতে ক্লিক করুন):
সঠিক উত্তর
1 (7.5)
বিস্তারিত ব্যাখ্যা ও বিশ্লেষণ:
Solution:
Let's say Karim's work rate per day = 1/x, where x is the days he takes alone
bablu's work rate per day = 1/5 (as he takes 5 days alone)
Together they take 3 days, so their combined rate = 1/3
ATQ,
(1/x) + (1/5) = 1/3
⇒ (5 + x)/5x = 1/3
⇒ 15 + 3x = 5x
⇒ 15 + 3x - 5x = 0
⇒ 15 - 2x = 0
⇒ 2x = 15
∴ x = 7.5
Therefore, Karim would take 7.5 days to build the table alone.
