Answer:

9 coins of 50paise and 18 coins of 25paise.

Step-by-step explanation:

Seeta Devi has Rs 9 in fifty-paise coins and twenty-five coins. She has twice as many twenty-five paise coins as she has fifty-paise coins.

Total money she had = Rs.9 = 900 paise.

Let the number of 50 paise coins be x.

Then according to the question the number of 25paise coins is = 2x.

Now, value of x coins of 50paise is = 50x

Again value of 2x coins of 25paise is = 25 × 2x = 50x

Total value of coins = 50x + 50x = 100x which is again equals to 900paise.

Framed Equation: 50x + 25 × 2x = 900

100x = 900

=> x = 9

Now, let's move to what we considered.

The number of 50paise coins = x = 9.

The number of 25paise coins = 2x = 2 × 9 = 18.

Therefore, the number of 50paise coins are 9 and the number of 25paise coins are 18.