(25000-f)(.03)+.05f=1100
750-.03f+.05f=1100
750+.02f=1100
.02f=350
f=$17500
So Mary invested $17500 @ 5% and 7500 at 3% to earn $1100 in interest.
84/2 = 42
42/2 = 21
21/3 = 7
7/7 = 1
84 = 2^2 * 3 * 7
This is a really vague question, but all i can assume from that is that all the sides of some triangle are congruent to their respective sides on the other triangle.