15 * 28 = 420. Should be your answer.
Answer:
Step-by-step explanation:
5k+ 6k+9k=20k
20k=£60
k=3£
£15, £18, £27
From V= 4/3*pi*r^3
<span>dV/dt = 4pi(r^2)dr/dt </span>
<span>so when dV/dt=30 and r = 19 </span>
<span>30 = 4pi(361)dr/dt </span>
<span>dr/dt = 30/[4pi(361)] </span>
<span>now in </span>
<span>A = 4pir^2 </span>
<span>dA/dt = 8pi(r)dr/dt </span>
<span>= 8pi(19)*30/[4pi(361)] </span>
<span>= you finish it.</span>
<span>HOPE THIS HELPS.
</span>
I think it’s the first one. 30:54 because 5 times 6 is 30 and 9 times 6 is 54.
