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1. A certain sum of money consists of 30 coins, some of which are 10 paisa coins and the rest are 5 paisa coins. If the total value of the coins is Tk.2, what is the number of 10 paisa coins?
- A. 10
- B. 10
- C. 10
- D. 10
Answer: Option A
Explanation:
x = number of 10 paisa coins;
y = number of 5 paisa coins .
so,x + y = 30
and x = 30 - y
ATQ,
10x + 5y = 200
Substitute for x.
10(30 - y) + 5y = 200
or,300 - 10y + 5y = 200
or, - 5y = - 100
or,y = 20
so,x = 30 - 20 = 10
∴ the number of 10 paisa coins is 10
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