Answer:
1 exponential decay and 78%
Let's call the unknown amount of money <em>x</em>
Betty spend 5/12 of her money (5/12)x and had 42 dollars left. Translated,

Solving,



Answer: $72
5b^3 sq rt of a
There's not enough a's
Answer:
passed: 164
failed: 41
Step-by-step explanation:
Let the failed students be x, then the passed students will be 4x.
x + 4x = 205
x = 205/5 = 41
4x = 4*41 = 164