Answer:
20km
Explanation:
Given that it takes a farmer 1 day to put up ⅓km fence, the length of fence he would put up in 6⅔ days would be calculated as follows:
Let x be length of the fence we are looking for. Thus,
⅓ km = 1 day
6⅔ = x
Cross multiply
⅓*x = 1*6⅔
⅓*x = 1*20/3
x/3 = 20/3
Multiply both sides by 3 to make x the subject of formula
x = (20*3)/3
x = 20
Length of fence he would put up in 6⅔ days = 20km