After 1 hour, 360 g decays to 180 g.
After another hour (total 2 hours), 180 g decays to 90 g.
After another hour (total 3), 90 g decays to 45 g.
After one more (total 4), 45 g decays to 22.5 g.
More quickly, with a half-life of 1 hour, the 360 g of starting material decays to
(360 g) / 2⁴ = 22.5 g
In general, if the half-life is 1 hour, then after <em>n</em> hours, an initial amount <em>A</em> of this substance decays according to
<em>A</em> / 2<em>ⁿ</em>
This is a 3 step problem. First you ignore the hole in the middle and find the volume anyways. Then you find the volume of the empty middle part. Then you can find the volume of the actual shape by subtracting them.
area of a circle is= pi r^2
Volume with hole: 5*5*pi*8=200pi
Volume of hole= 1.5*1.5*pi*8= 18pi
Volume of doughnut = 200pi-18pi=182pi=571.769863u^3
r is the radius which is half of the diameter.
pi is a big number but you can use 3.14
the formula for finding the volume is area of base times height. That's why i multiplied it by 8.]
I hope this helps
Answer: B
Step-by-step explanation:
Answer:
$2.48
Step-by-step explanation:
He paid $20 and got $12.56 back so you subtract
20-12.56=7.44
So his total was 7.44 and he bought 3 bags so divide to find the individual price
7.44/3=2.48
So $2.48
