Discuss Forum
1. The electricity bill of a certain establishment is partially fixed and partially varies as the number of units of electricity consumed. Wen in a certain month 540 units are sonsumed. the bill is TK 1800. In another month 620 units are consumed are the bill is Tk 2040. Inayet another month if 500 units are consumed what would be the bill (in Tk) for that month?
- A. 1950
- B. 1950
- C. 1950
- D. 1950
Answer: Option D
Explanation:
মনেকরি,
নির্ধারিত সর্বনিম্ন চার্জের পরিমাণ = x টাকা
এবং প্রতি ইউনিট বিদ্যুতের দাম = y টাকা
প্রশ্নমতে,
540y + x = 1800.......... (i)
620y + x = 2040.......... (ii)
(i) - (ii)⇒
- 80y = - 240
⇒ y = 3
.: (i) ⇒
540 x3 + x = 1800
⇒1620 + x = 1800
⇒ x = 1800 - 1620
⇒ x = 180
.: 500 ইউনিটের জন্য মোট খরচ
= 180 + (500 × 3)
= 180 + 1500 = 1680 টাকা
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