<span>1) y varies directly with x, then we have: y = kx, k is the constant of variation
y = kx
14 = - 4k
k = 14/- 4, or - 7/2, or - 3.5
y = kx
y = - 3.5(- 6)
y=21
2) </span><span>201.6 is the right answer.see the procedure used in Q1.
3) K = y/x
= 9/12
= 3/4</span>
Answer:
59.44%
Step-by-step explanation:
<em>
</em>
<em>
</em>
<em>Where
= mass remaining</em>
<em>
=original mass.</em>
<em>t= time </em>
<em>
=half life</em>
=1599, t= 1200,
=226,
=?

n= 0.750469

=134.3367amu
percentage of mass remaining =
*100%
= 59.44%
15/24 5/x
cross multiply
15x=120
x=8