Answer:
Amount of Niobium-91 initially
= 300/91 =3.2967mol
2040 years = 3 ×680 = 3 half-lives
therefore, amount left = 0.4121mol
mass of Niobium-91 remaining = 0.4121 ×91 =37.5g
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Answer:
105 degrees
Step-by-step explanation:
You need to understand the properties of corresponding angles and supplementary angles.
Answer: 45
Step-by-step explanation:
In 2016, 1 out of every 5 people under the age of 50 used a cell phone to read e-books. This means that 2 out of every 10 people under the age of 50 used a cell phone to read e-books. Also, 3 out of every 15 people under the age of 50 used a cell phone to read e-books.
Therefore, if there were x people under the age of 50 in 2016, then the number that used a cell phone to read e-books would be
1/5 × x = x/5
If there were approximately 225 million people under the age of 50 in 2016, then the number that were likely to have read an e-book on a cell phone is
225/5 = 45 people.
Answer:
$6750 in the bank account and $20,250 in the stock fund
Step-by-step explanation:
If B is the money they put in the bank and S is the amount they put in the stock fund, then:
B + S = 27000
1.024 B + 1.072 S = 1.06 × 27000
Solving the system of equations:
1.024 (27000 − S) + 1.072 S = 28620
27648 − 1.024 S + 1.072 S = 28620
0.048 S = 972
S = 20250
B = 27000 − S
B = 6750
They should put $6750 in the bank account and $20,250 in the stock fund.
