Answer:
A.
In 4231, the value of the digit 3 is 110 less than the value of the digit 3 in 3421.
Step-by-step explanation:
We can see that the value of 3 In 4231 is in ten while the value of 3 in 3421 is in thousands.
So to get the actual division factor, let's take 3300 and divide it by 30,
3300/30 = 110
So it's clear already, that the value of 3 in 4231 is 110 times less to the value in 3421
Staals half
1 gram left
0.3 grams left
half lives are normally written in years
it goes likt this

A=final amount
P=initila amount
t=time elapsed
h=time half life is (same units as time)
let's use days as the units of time
we are given
initial amount=1gram
final amount=0.3gram
time=4 days
so

solve for h

take the ln of both sides


times both sides by h

divide both sides by ln(0.3)

use calculator
h=2.30287
3 sig figs
h=2.303 days
A= 30
Explanation: 88-58=30
72:80
9:10
Divide 72 and 80 by 8 to simplify it and get the ratio