4. The parametric curve (x, y) = (2 cos θ , 2 sin θ + 3 cos θ), 0 ≤ θ ≤ 2π represents an ellipse. Find the foci that lie in the first quadrant.

1. There was a class of 41 people divided into three groups A, B, and C, and the average score of subject natural’s test was 89.7 points; the average score of group A was 89.8 points; the average score of A, B combination was 88.5 points; the average score of A and C combination was 91 points, and how many people were in each of groups A, B and C?