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
Answer:
105 rooms
Step-by-step explanation:
quarter=1/4
total rooms=140
rooms cleaned=1/4×140=35
140-35=105
therefore total rooms remaining are 105 rooms
hopes this helps
brainliest pls
Answer:
slope is undefined
Step-by-step explanation:
Calculate the slope m using the slope formula
m = 
with (x₁, y₁ ) = (- 2, 9 ) and (x₂, y₂ ) = (- 2, - 5 )
m =
=
= 
Since division by zero is undefined then the slope is undefined
Answer:
B
Step-by-step explanation: