Let the number of coins of fifty paise are x
Number of coins of twenty five paise are 2x
Amount due to fifty paise coins = \(\frac{50\times x}{100}\)= 0.50x
Amount due to twenty five paise coins = \(\frac{25\times2x}{100}\) = 0.50 x
According to the question total amount = Rs 9
0.50x + 0.50x = 9
x = 9
Therefore the number of coins of fifty paise are 9
Number of coins of twenty five paise are 2x = 2\(\times\)9 = 18