X = amount of 50% solution
y = total amount after mixing
Note that the amount of alcohol in the 20% solution is 80 (0.2) = 16 oz.
We have 2 unknowns, so we need 2 equations:
first, we can write the equation for the total volume:
y = x + 80
next, apply the percentages to get an equation for the amount of alcohol:
0.4 y = 0.5 x + 16
Finally, solve the pair of equations (in this case, by substitution of the 1st into the second:
0.4 (x + 80) = 0.5x + 16
0.4 x + 32 = 0.5X + 16
rearrange and combine like terms:
0.1x = 16
x = 160
from the 1st equation:
y = 160 + 80 = 240
Every 56 seconds, the radioactive substance is divided in half.
224 / 56 = 4
We need to cut the substance in half 4 times.
896 / 2 = 448
448 / 2 = 224
224 / 2 = 112
112 / 2 = 56
After 224 seconds, there will be 56 grams of the radioactive substance left over
2/7x - 2/5x = 8
multiply both sides by 35
= 10x - 14x = 280
combine 10x and 14x
= -4x = 280
divide both sides by -4
x= -70
Answer:
Your answer would be I= (2,-1) J= (2,-3) and K= (5,-2)
Step-by-step explanation:
By reversing the coordinates across the x-axis, you will reverse the y coordinate (ex. 4,1 will become 4,-1). If you reverse the coordinates across the y-axis, you will reverse the x coordinate.
