Number of 1 rupee coins = x say.
Number of 50 paise coins = 3 × x = 3x
The value of total coins = \(\frac{3x}2\) + x
[∵50 paisa coins of 3x = ₹ \(\frac{3x}2\)
According to the sum
⇒ \(\frac{3x}2\) + x = 35
⇒ \(\frac{3x\,+\,2x}{2}\) = 35
⇒ 5x = 2 × 35
⇒ x = 2 × \(\frac{35}2\)
∴ x = 14
∴ Number of 1 rupee coins = 14
Number of 50 paisa coins = 3 × x = 3 × 14 = 42