Sirisha has Rs.9 in fifty – paisa and twenty paise coins. She has twice as many twenty five paise coins as she has fifty paise coins. How many coins of each kind does she have? - Sri Chaitanya Infinity Learn Best Online Courses for NCERT Solutions, CBSE, ICSE, JEE, NEET, Olympiad and Class 6 to 12

A
5 coins of 50 paise and 10 coins of 25 paise
B
20 coins of 50 paise and 10 coins of 25 paise
C
18 coins of 50 paise and 9 coins of 25 paise
D
9 coins of 50 paise and 18 coins of 25 paise

Solution:

Let us consider that she has ‘x’ number of coins of 50 paise and ‘y’ number of coins of 25 paise.
Amount of 50 paisa coins =

\frac{50}{100} \times x = 0.5 x

Amount of 50 paisa coins =

\frac{25}{100} \times y = 0.25 y

Given, total money she has is Rs.9
i.e., 0.5x + 0.25y = 9 …(i)
Also, she has twice as many twenty-five paise coins as she has fifty paise coins
i.e, y = 2x …(ii)
Put the value of y in eq(i), we get
0.5x + 0.25(2x) = 9
0.5x + 0.5x = 9
x = 9
y = 2(9) = 18
Hence, she has 9 coins of 50 paise and 18 coins of 25 paise.
Therefore, 4 is the correct option.

Solution:

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