Ms. Lew has a bag of 3D shapes she uses to teach her 3rd graders. The bag contains 200 cubes, spheres, and pyramids. She records the shape she pulls out of the bag for 20 trials, replacing the shape each time. The following table summarizes her results.
Shape Frequency
Cube 3
Sphere 8
Pyramid 9
Based on the results in the table, about how many of the shapes in the bag are spheres?
A. 40
B. 67
C. 80
D. 160
B. 67
To determine this, we can calculate the probability of selecting a sphere in each trial by dividing the frequency of spheres (8) by the total number of trials (20).
8/20 = 0.4
Then, we can multiply this probability by the total number of shapes in the bag to estimate the number of spheres in the bag.
0.4 x 200 = 80
Therefore, Ms. Lew has about 80 spheres in the bag.