The student must have thought that every single arrowhead is a line of symmetry, so since there are 10 arrowheads, there must be 10 lines of symmetry. This is incorrect because if you look closely at the diagram, each line has 2 arrowheads, so the student is overcounting by a factor of 2. They should have just counted the number of lines, not arrowheads. Therefore, there must be 10/2 = 5 lines of symmetry, not 10. Hope this helps!
<span>The total number (n) = 28. This includes the number of cats (c) and the number of dogs (d), which is three times the number of cats. Therefore n = c + d and 28 = c + 3c. 28 = 4c. C = 28/4. C = 7. Kim trained 7 cats.</span>
