Phytoremediation is the use of plant growth to purify pollutants from soil, water, or air. Suppose that a crop of brake ferns can remove 15 milligrams per square meter of a particular pollutant from the soil in 20 weeks. After, 20 weeks the ferns are harvested and a new crop is planted. If C represents the number of corps of brake ferns needed to phytoremediate soil contaminated with 170 mg per square meter of the pollutant down to healthy levels of 5 mg per square meter, which equation best models the situation ?
The correct option is C 170−15C=5
Step I : Underline the words
'' Phytoremediation is the use of plant growth to purify pollutants from soil, water, or air. Suppose that a crop of brake ferns can remove 15 milligrams per square meter of a particular pollutant from the soil in 20 weeks. After, 20 weeks the ferns are harvested and a new crop is planted. If C represents the number of corps of brake ferns needed to phytoremediate soil contaminated with 170 mg per square meter of the pollutant down to healthy levels of 5 mg per square meter, which equation best models the situation ? ''
Step II: Recognize the variable
Already given no. of crops = C
Step III: Form an equation.
The initial level of pollutant = 170mg/m2
As each crop removes 15 mg per square meter of pollutant in 20 weeks.
You can easily eliminate options B and D.
Now, let’s form the equation
As each crop removes 15mg/m2 of pollutant, then C crops will remove 15C mg/m2 of pollutant.
Therefore, to break down pollutant from 170mg/m2 to 5mg/m2, in 20 weeks,
we have 170−15C=5.
Hence, option C is correct.
Step I : Underline the words
'' Phytoremediation is the use of plant growth to purify pollutants from soil, water, or air. Suppose that a crop of brake ferns can remove 15 milligrams per square meter of a particular pollutant from the soil in 20 weeks. After, 20 weeks the ferns are harvested and a new crop is planted. If C represents the number of corps of brake ferns needed to phytoremediate soil contaminated with 170 mg per square meter of the pollutant down to healthy levels of 5 mg per square meter, which equation best models the situation ? ''
Step II: Recognize the variable
Already given no. of crops = C
Step III: Form an equation.
The initial level of pollutant = 170mg/m2
As each crop removes 15 mg per square meter of pollutant in 20 weeks.
You can easily eliminate options B and D.
Now, let’s form the equation
As each crop removes 15mg/m2 of pollutant, then C crops will remove 15C mg/m2 of pollutant.
Therefore, to break down pollutant from 170mg/m2 to 5mg/m2, in 20 weeks,
we have 170−15C=5.
Hence, option C is correct.
