DDT (dichlorodiphenyltrichloroethane) was used extensively from 1940 to 1970 as an insecticide. It still sees limited use for control of disease. But DDT was found to be harmful to plants and animals, including humans, and its effects were found to be lasting. The following table shows what can be expected of 100kg of DDT that has seeped into the soil. t = years since application 0 1 2 3 D = DDT remaining 100 95 90.25 85.74 What is the half-life of DDT in the soil? That is, how long will it be before only 50kg of DDT remain? a) 15.5 years b) 14.5 years c) 13.5 years d) 12.5 years
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DDT (dichlorodiphenyltrichloroethane) was used extensively from 1940 to 1970 as an insecticide. It still sees limited use for control of disease. But DDT was found to be harmful to plants and animals, including humans, and its effects were found to be lasting. The following table shows what can be expected of 100kg of DDT that has seeped into the soil.
| t = years since application |
0 | 1 | 2 | 3 |
| D = DDT remaining |
100 | 95 | 90.25 | 85.74 |
What is the half-life of DDT in the soil? That is, how long will it be before only 50kg of DDT remain?
a) 15.5 years
b) 14.5 years
c) 13.5 years
d) 12.5 years
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