She may have used a wrong operation to get this answer. 73 is not the correct answer, and you can prove it using a calculator or longhand. The correct answer is 6888.
How to get answer by Mimiwhatsup (In Decimal Form):
Answer in Fraction Form: 
Answer:
C, as q = 62.
Step-by-step explanation:
When you have an equation, your goal is to get the letter you are solving for alone. To do this, you employ a simple rule: what you do to one side of the equals sign, you must do the other.
To isolate q in -55 + q = 7, you must add 55 to the left side. q is now alone. However, because we added 55 to the left side, we must also do it to the right! 7 + 55 = 62, so the new right side is 62. Hence, we get to this:
q = 62
The answer is now in plain sight!
Answer: A reasonable estimate of the minimum is 20.
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
Please give brainliest
