The price of commodity X increases by 40 paisa every year, while the price of commodity Y increases by 15 paisa every year. If in 2001, the price of commodity X was Tk 4.20 and that of Y was Tk. 6.30, in which year commodity X will cost 40 paisa more than the commodity Y?
বিকল্পসমূহ (নিজের উত্তর যাচাই করতে ক্লিক করুন):
সঠিক উত্তর
3 (2011)
বিস্তারিত ব্যাখ্যা ও বিশ্লেষণ:
Solution:
Suppose commodity X will cost 40 paise more than Y after P years.
Then,
(4.20 + 0.40P) - (6.30 + 0.15P) = 0.40
⇒ 4.20 + 0.40P - 6.30 - 0.15P = 0.40
⇒ 0.25P - 2.10 = .40
⇒ 0.25P = 0.40 + 2.10
⇒ 0.25P = 2.5
⇒ P = 2.5/0.25
∴ P = 10
X will cost 40 paise more than Y 10 years after 2001 which is 2011.
