Question

I calculated these solutions myself but I have doubt in my answers, I'd appreciate some confirmation.

a. The U.S. average yield of corn is 153 bushels/acre.

Does this agree with the 2009 international average as

defined by the United Nation

Answer 1

a)

153 bushels/acre = 153*56 lb / acre = 153*56*453.6/100 hectogram / acre = 153*56*453.6/100 *0.405 hectogram/hectare

= 15740.1 hectogram / hectare

51219 hectogram / hectare estimate from 2009 is almost 3.25 times.

b)

Possible difference might be due to the fact that one is shelled while other might be cobbed.

c)

Surface area of earth = 4*pi*r^2 = 4*3.14*6371^2 = 509805891 km^2

Land area of earth = 30 % of 509805891 = 0.3*509805891 = 152941767 km^2

Crop land = 10 % of 152941767 = 0.1*152941767 = 15294176.7 km^2 = 15294176.7 *10^6 m^2 = 15294176.7 *10^6 / 10,000 hectare ^2

= 1529417672.88 hectare^2

Total corn produce in a year = 51219*1529417672.88 hectogram = 51219*1529417672.88 *100/1000 kg

= 7,833,524,378,724 kg

= 7.8*10^12 kg

d)

77 g gives 83 kcal.

2000 cal will come from 2000*77 / 83 = 1855 g = 1.855 kg

Total persons = 7.8*10^12 / 1.855 = 4,221,964,437,883 people

= 4.22*10^12 people

e)

7.8*10^12 kg wil yield 7.8*10^12 / 7 kg of meat. = 1.1*10^12 kg of meat.

Total Calories = 1.1*10^12 *200 / 85 *1000 kcal = 2.588*10^15 kcal

2000 calories per person.

Total person = 2.588*10^15 / 2000 = 1.294*10^12 people

f)

Population of earth = 6*10^9

g)

Yes, it is possible.