Dissecting a Triangle

ABC is a triangle. D and E are on AB and AC respectively. BE and CD intersects at F. The areas of triangles CEF, BDF, and BCF are 10, 15, and 20 respectively.  What is the area of quadrilateral AEFD?

Angle LEO

A regular 26-sided polygon has its 26 vertices marked as A, B, C, .... , Z clockwise. What's the angle LEO? (Please keep one digit after decimal point.)

Sum of 2020 Numbers

N is the sum of 2020 numbers: N = 20 + 2020 + 202020 + 20202020 + ... + 2020...2020. What's the last four digits of N?