A forester is planting trees. The forest already has 30 native trees. On Monday he triples the number of total trees in the forest by planting new trees. On Tuesday, he plants a third of the amount he planted on Monday. How many trees has the forester planted in total?
Thoughts? Step-by-step reasoning:
Let M be the number of trees he plants on Monday. On Monday the forest was three times larger from the trees that were originally there and the M trees: 3 * 30 = 30 + M trees. So, 90 = 30 + M. And, M = 60 trees. On Tuesday, he planted 60 trees / 3 = 20 trees. In total, he has planted 60 trees + 20 trees = 80 trees.
Thus, the answer is 80.