Answer:
31.4 meters
Step-by-step explanation: use the formula 2 times pi times 5 then you just plug in 5 into the radius
Answer:
(6,0)
Step-by-step explanation:
The given system has equations:
Multiply the top equation by 2 to get:
Subtract the top equation form the bottom equation to get:
Put y=0 into
Therefore the solution is (6,0)
Answer:
In this case, the equation that models the value of an initial investment of P dollars in t years at an annual interest rate of r is given by A = Pert.
Step-by-step explanation:
Try this:
1) note that weight of pure antifreeze before mixing and after mixing is the same. So, if 'x' is weight of pure antifreeze in 50% solution, it is possible to make up equation before mixing: 0.5x+0.2*90.
2) there are 0.2*90=18 gal. of pure antifreeze in the 20% solution. If 'x' gal. is the weight of pure antifreeze in 50% sol. and 18 gal. is the weight of pure antifreeze in 20% sol., it is possible to make up an equation after mixing: 0.4(x+18).
3) using the both parts: 0.5x+0.2*90=0.4(x+18) ⇒ x=54 gal. of <u>pure</u> weight.
4) to find 50% solution of 54 gal. pure weight just 54:0.5=108 gal.
Answer: 108 gal.