Assume the cost of the each table is Rs x and cost of each chair is Rs. y.
ATQ
3x + 20 y = 1850 ...(i)
x = 75 + y ....(ii)
Put value of x in equation (ii)
3(75 + y) + 20 y = 1850
225 + 23 y = 1850
23 y = 1625
y = Rs 70.65
x = 75 + 70.65
x = Rs 145.65
Hence the cost of one table is Rs 145.65 and cost of one chair is Rs 70.65.