Just multiply them so first multiply 2.7 times .9 and then times your answer by .6
Answer:
20
Step-by-step explanation:
I'm pretty sure it is 155
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
