Answer:
Mr. Smith collects $5748 from selling the can.
Step-by-step explanation:
Given total number of cans = 
Selling price of one can = $15.
Now remaining number of cans = total number of cans - sold number of cans =
For remaining number of cans he gives a discount of 20% each,
∴ Selling price of one can = 
∴ Selling price of 54 cans = 
So total money he earns = 
.
Thus Mr. Smith earns $5748 by selling the cans.
As usual, draw a diagram. You can easily see that if you are x away from the wall,
<span>the angle of elevation of the bottom of the screen (A) is </span>
<span>cotA = x/3 </span>
<span>A = arccot(x/3) </span>
<span>angle B to the top is </span>
<span>cotB = x/10 </span>
<span>B = arccot(x/10) </span>
<span>So, since θ = B-A </span>
<span>dθ/dt = dB/dt - dA/dt </span>
<span>= -3/(x^2+9) + 10/(x^2+100) </span>
<span>= 7(x^2-30)/((x^2+9)(x^2+100)) </span>
<span>so, at x=30 </span>
<span>dθ/dt = 203/30300</span>
Answer:
Jackie sold 12 cars.
Step-by-step explanation:
If we call the number of cars Oscar sold O, and the number of cars Jackie sold J, we can say the following:
O = J + 6
As Oscar sold 6 cars more than Jackie.
Together, they sold 30 cars.
O + J = 30
Since we know that:
O = J + 6
... we can put this into our previous equation.
O + J = 30
(J + 6) + J = 30
J + J + 6 = 30
2 * J + 6 = 30
Subtract 6 from both sides:
2 * J = 24
Divide both sides by 2:
J = 24 / 2
J = 12
Jackie sold 12 cars.
