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a student wants to estimate the population size and density of birch trees in a woodlot measuring 100 m by 100 m. On a diagram of the woodlot, she splits the area into a 10 by 10 grid and randomly selects 10 sample quadrants - (0,0), (1,4), (2,6), (3,9), (4,3), (5,5), (6,1), (7,8), (8,2), and (9,7). These areas of the woodlot are marked off, and the birch trees are counted. She finds 15, 25, 40, 20, 10, 30, 25, 5, 15, and 35 trees in the ten quadrants. Estimate the density and size of the birch-tree population in the woodlot.

An object has a length of 5.0 cm, a height of 3.0 cm and a width of 15.0 cm. It has a mass of 24 grams. What is its density

volume= (15cm)(3cm)(5cm)=225cm^3
mass=24g
density=mass/volume
density=24/225=8/75g.cm^-3

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