Assume the number of 25 paise coins, 50 paise coins are x, y respectively.
ATQ
x + y = 140..(i)
25x + 50 y = 5000
x + 2y = 200...(ii)
Equation (ii) - Equation (i)
x + 2y -x - y = 200 - 140
y = 60
x = 80
Hence the number of 25 paise coins, 50 paise coins are 80, 60 respectively.