173: Bathtubs

Math is not always as easy for journalists as it is for you. Help this one with some of his calculations and assumptions.

67: Two Questions of Average Difficulty

From Gabriel Rosenberg via email

True or False?

If my stock increases in value by 28% one year, and then decreased in value by 2% the following year, then on average it increased by 13% per year.

If I powerwalk to school at a constant speed of 4 miles per hour, and then saunter home at a constant speed of 2 miles per hour, then I averaged 3 miles per hour for my trip.

13: Strange Triangles

Triangle ABC is congruent to triangle DEF.
In triangle ABC, side AB measures 9, side BC measures 3x+18, and side CA measures 7.
In triangle DEF, side DE measures 9, side EF measures 2x+26, and side FD measures 7.

What equation would help you to solve for the side length of BC and EF?

(Actual question in an on-line geometry course.)

What would you do to fix this question?