Answer:
We need 540 grams of 0.5% hydrocortisone cream
Step-by-step explanation:
Lets call x the amount of grams needed. This means that the combined cream will have 180+x grams. We want x such that
x * 0.005 + 180*0.025 = (180+x)*0.01
Hence
0.005x + 4.5 = 1,8+0.01x
Lets put the x in the same side and take common factor
4.5-1.8 = 0.01x-0.005x
2.7 = (0.01-0.005)x = 0.005x
As a result
x = 2.7*0.005 = 540
We need 540 grams.
<span>They use 9 blocks each, a total of 18 blocks.
Bill: 4b + 2
Ron: 8b - 5
To look for the value of b; I assume that both used the same number of blocks.
4b + 2 = 8b - 5
4b - 8b = -5 -2
-4b = -7
-4b/-4 = -7/-4
b = 1.75</span>
Bill: 4b + 2 where b = 1.75 ; then, 4(1.75) + 2 = 7 + 2 = 9
<span>Ron: 8b - 5 where b = 1.75; then, 8(1.75) -5 = 14 - 5 = 9</span>
Answer:
24
Step-by-step explanation:
Answer: It will take about 77 years (76.8 years).
Step-by-step explanation: Time is given by the equation: N=No.e^kt. You know that the concentration has to be 15% from the original so N=15 and No=100. To determine k, you have to look at the half-life. k=ln(0.5)/half-life time. For 28 years, k=-0.0247. Replacing it back into the N=No.e^kt equation, the answer will be 76.8 years.
