Tractors

Six tractors started plowing the field, and work together took 12 days.

Agronomist hesitates to:

A) after two days, withdraw two tractors or
B) after three days, withdraw three tractors.

Help him which of these two cases will be plowing done sooner.

Result

x=

Yes

No

Step-by-step explanation:

$$\begin{gathered} v=\frac{1}{6\cdot 12}=\frac{1}{72}\doteq 0.0139 \\ 6\cdot 2\cdot v+4\cdot A\cdot v=1 \\ 6\cdot 2\cdot 0.013888888888889+4\cdot A\cdot 0.013888888888889=1 \\ 0.055556A=0.833333 \\ A=\frac{0.83333333}{0.05555556}=15 \\ A=15 \\ 6\cdot 3\cdot v+3\cdot B\cdot v=1 \\ 6\cdot 3\cdot 0.013888888888889+3\cdot B\cdot 0.013888888888889=1 \\ 0.041667B=0.75 \\ B=\frac{0.75}{0.04166667}=18 \\ B=18 \\ A<B \\ x=1 \end{gathered}$$

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