Question

A sum of Rs 36.90 is made up of 180 coins which are either 10 paise coins or 25 paise coins. Determine the number of each type of coins.

• A. 126 of 10p coins and 54 of 25p coins
• B. 54 of 10p coins and 126 of 25p coins
• C. 90 of 10p coins and 90 of 25p coins
• D. None of the above

Answer 1

Answer: (B)

54 of 10p coins and 126 of 25p coins

Answer 2

Let number of 10 paise coins be and number of 25 paise coins be$(180-x)$
$\frac{1}{10} \times (x) + \frac{1}{4} \times (180 - x) = 36.90 \\\\$
$\Rightarrow \frac{x}{10} - \frac{x}{4} + 45 = 36.90 \\\\$
$\Rightarrow \frac{3x}{20} = 8.10 \\\\$
$\Rightarrow x = 8.10 \times \frac{20}{3} = 54$
The correct answer is (B) :54 of 10p coins and 126 of 25p coins