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
45 divided by 50= 90%
0.9*16.50=14.85
Answer:

Step-by-step explanation:
we have

where
t is the time in seconds
h is the dolphin's height in feet
we know that
When the dolphin return to the water the value of h(t) is equal to zero
so
For h(t)=0


Simplify



see the attached figure to better understand the problem
Well if she drinks the same amount every day it should last her 3 days because 4 cups = 1 quart

6.25 feet. The formula is: