If I counted correctly, the answer would be 52/150. You just need to simplify the fraction. I'll recount soon, and update if it changes.
Circumference = π × diameter
π × 9 = 28.274333882
To 1dp = 28.3
Circumference = 28.3 inches
18 kg of 15% copper and 72 kg of 60% copper should be combined by the metalworker to create 90 kg of 51% copper alloy.
<u>Step-by-step explanation:</u>
Let x = kg of 15% copper alloy
Let y = kg of 60% copper alloy
Since we need to create 90 kg of alloy we know:
x + y = 90
51% of 90 kg = 45.9 kg of copper
So we're interested in creating 45.9 kg of copper
We need some amount of 15% copper and some amount of 60% copper to create 45.9 kg of copper:
0.15x + 0.60y = 45.9
but
x + y = 90
x= 90 - y
substituting that value in for x
0.15(90 - y) + 0.60y = 45.9
13.5 - 0.15y + 0.60y = 45.9
0.45y = 32.4
y = 72
Substituting this y value to solve for x gives:
x + y = 90
x= 90-72
x=18
Therefore, in order to create 90kg of 51% alloy, we'd need 18 kg of 15% copper and 72 kg of 60% copper.
Sorry I don’t see any images or diagrams I’m not sure
You must drive more than 40 miles to make option A the cheaper plan
<em><u>Solution:</u></em>
Two payment options to rent a car
Let "x" be the number of miles driven in one day
<em><u>You can pay $20 a day plus 25¢ a mile (Option A)</u></em>
25 cents is equal to 0.25 dollars
OPTION A : 20 + 0.25x
<em><u>You pay $10 a day plus 50¢ a mile (Option B)</u></em>
50 cents equal to 0.50 dollars
Option B: 10 + 0.50x
<em><u>For what amount of daily miles will option A be the cheaper plan ?</u></em>
For option A to be cheaper, Option A must be less than option B
Option A < Option B
Solve the inequality
Add -0.50x on both sides
Add - 20 on both sides,
Divide both sides by 0.25
Thus you must drive more than 40 miles to make option A the cheaper plan
