30. is 8 [-5] [3] [-2] -2
Answer:
21 is 20% of 105
Step-by-step explanation:
20% * x = 21
20/100 * x = 21
x = 21 * 100/20
x = 105
If you are using a calculator, simply enter 21×100÷20, which will give you the answer.
Answer:
quotient of 3x3 - 25x2 + 12x - 32 and x - 8 is 3x^2-x+4
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.
