Answer: See explanation
Step-by-step explanation:
Area of one rectangle: l × w
7 × 4 = 28
28 in²
Total area: 28 × 4 = 112
112 in²
The Cena can take 7 courses
We have given that the karate charges $35 for the first course and $22.50 for each course after that. Our total is $170.
<h3>What is the condition we can write here?</h3>

for solving this linear equation
First, subtract 35 from both sides.

isolate x so divide both sides by 22.50.

Therefore we get x = 6
Remember to add the additional class, so x is actually 7.
So,the Cena can take 7 courses.
To learn more about the linear equation visit:
brainly.com/question/1549055
Let r be the decay rate (time in minutes) 17 = 20 e^(5r) 0.85 = e^(5r) ln 0.85 = 5r similarly, ln 0.5 = hr ... where h is the half-life, so dividing the 2 equations, ln 0.85 / ln 0.50 = 5r / hr = 5/h h = 5 ln 0.50 / ln 0.85 h = 21.3 min b) 1/20 = 0.05, so ln 0.85 = 5r ln 0.05 = tr t = 5 ln 0.05 / ln 0.85 t = 92.2 min
The first pump empties half the pond in 3 hours, so in 1/6 that time (1/2 hour), it empties (1/6)·(1/2) = 1/12 of the pond.
The second pump empties the other 5/12 of the pond in that half hour, so has a pumping rate of (1/2 h)/(5/12 pond) = (6/5 h)/pond.
The second pump could do the entire job alone in 1 hour and 12 minutes.