18. The depth of a pond is 180 cm and is being reduced by 1 cm per week. The depth of a second pond is 160 cm and is being reduced by cm per week. If the depths of both ponds continue to be reduced at these constant rates, in about how many weeks will the ponds have the same depth ?

Answer and Explanation

Your Answer is

Correct Answer is H

Explanation

Assuming the depth of the pool is y, in week x, the depth of the first pool can be expressed as y = 180 - x, and the depth of the second pool can be expressed as y = 160 - 0.5x so that the two pools When the depth is equal, the two equations are subtracted, and the solution is x = 40. That is, it takes 40 weeks to equalize the depths of the two pools. The answer is H.