If the productions of wheat in Bihar in the years 2001, 2002, 2003 and 2004 increase by 20%. 25%, 28% and 35% respectively; what will be the percentage increase in the average production of the state for the given years ?

Increase in wheat production in Bihar in the year :

2001 = $$\frac{120}{100}$$ * 2800 = 3360

2002 = $$\frac{125}{100}$$ * 2700 = 3375

2003 = $$\frac{128}{100}$$ * 2800 = 3584

2004 = $$\frac{135}{100}$$ * 3800 = 5130

=> Total new production = 3360 + 3375 + 3584 + 5130 + 2100 + 3800 + 3600 = 29949

Total earlier production = 2800 + 2700 + 2800 + 3800 + 2100 + 3800 + 3600 = 21600

=> Increase = 29949 - 21600 = 8349

=> Average increase = $$\frac{8349}{7}$$

$$\therefore$$ Required % increase = $$\frac{\frac{8349}{7}}{\frac{21600}{7}}$$ * 100 = 38.7%