Try, please, this:
1) Imagine, that pharmacist used 'x' gr. of 40% solution and 'y' of 70% solution.
Together (20 gr. of 52% sol.) it will be x+y=20.
2) From other side, the pharmacist combined 40x and 70y gramms, after obtaining together it is 52(x+y) gramms. In other words 40x+70y=52(x+y)
3)

Answer: 8 gr. of 70% solution and 12 gr. of 40%.
The residual value or some may term it the salvage value is the value of an item after a certain period of time. Let x be the original msrp (manufacturer suggested retail price), we can calculate for the salvage value as follows:
12,780 = 0.72x
The value of x from the equation generated above is 17,750. Therefore, the original msrp is equal to $17,750.
Answer:
Step-by-step explanation:
Sample size = 95
X=cash carried by the persons
x bar = 8.00
s = sample std dev = 2.50
Std error = 
Hence Z score would be


-0.00
b) 
c) 95% conf interval margin of error = ±
=±0.54782
Confi interval = (8-0.5027, 8+0.5027)
= (7.4923, 8.5027)
C)If conf level increases, then width of interval would increase since critical value would increase.
If sample size increases std error would decrease and hence margin of error.
So interval would decrease.
Answer:
a. Alice
b. Briana
c. 0.51 minutes
Step-by-step explanation:
a. Alice formula is valid for any t > 0 minutes, but Briana formula is only valid for
2t - 1 > 0
2t > 1
t > 1/2 minutes
b. They finish when their covered distance is equal to 5 kilometers. For Alice:
t/4 = 5
t = 5*4 = 20 minutes
For Briana:
√(2t - 1) = 5
2t - 1 = 5²
2t = 25 + 1
t = 26/2
t = 13 minutes
c. They are side by side when they have covered the same distance, that is:
t/4 = √(2t - 1)
(t/4)² = 2t - 1
t²/16 = 2t - 1
t² = 16*(2t - 1)
t² = 32t - 16
t² - 32t + 16 = 0
Using quadratic formula:







Only the second answer has sense for this problem because the race already finished before they spent 31.49 minutes in it.