How to solve for a variable
2 answers:
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Answer:
318.2 ml
Step-by-step explanation:
Jamie has 100 ml of a 50% isopropyl alcohol solution.
She wants to prepare a solution of 85% by adding 96% solution of isopropyl alcohol solution.
Let the amount of 96% solution required = x ml
Final amount of 85% isopropyl alcohol solution = (100 + x) ml
Therefore, equation for this situation will be,
100 × (50%) + (x) × (96%) = (100 + x) × (85%)
100(0.5) + 0.96x = 0.85(100 + x)
50 + 0.96x = 85 + 0.85x
0.96x - 0.85x = 85 - 50
0.11x = 35
x =
x = 318.18 ml
≈ 318.2 ml
Therefore, she will require 318.2 ml of 96% isopropyl alcohol solution.
Answer: 0.49 ± 0.0237
Step-by-step explanation: A interval of a 99% confidence interval for the population proportion can be found by:
± z.
is the proportion:
=
= 0.49
For a 99% confidence interval, z = 2.576:
0.49 ± 2.576.
0.49 ± 2.576.
0.49 ± 2.576.(0.0092)
0.49 ± 0.0237
For a <u>99% confidence interval</u>, the proportion will be between 0.4663 and 0.5137 or 0.49 ± 0.0237