175 mL at 25% concentration of alcohol contains 0.25 (175 mL) = 43.75 mL of alcohol. If <em>v</em> is the amount of the 70% solution that you use, then that amount contains 0.7<em>v</em> mL of alcohol.
Mixing these two yields a total volume of 175 mL + <em>v</em>, and it contains 43.75 mL + 0.7<em>v</em> alcohol. You want to end up with a concentration of 45%, which means the ratio of the amount of alcohol to the total volume needs to be 0.45:
(43.75 mL + 0.7<em>v</em>) / (175 mL + <em>v</em>) = 0.45
Solve for <em>v</em> :
43.75 mL + 0.7<em>v</em> = 0.45 (175 mL + <em>v</em>)
43.75 mL + 0.7<em>v</em> = 78.75 mL + 0.45<em>v</em>
0.25<em>v</em> = 35 mL
<em>v</em> = 140 mL
2+2=2x+2
-2 to both sides
2=2x
Divide 2
X=1
Answer: 1/8 km
Step-by-step explanation:
3/8 * 1/3 = 1/8
The probability that x >17 will be found as follows:
the z-score is given by:
z=(17-15.2)/0.9=2
Thus
P(X>17)=1-P(x<17)=P-(z=2)
=1-0.9772
=0.0228
9=5 -y/3
-5
3=-y/3
cross multiply
1=-y
y=-1
