Answer:
n = 30
Step-by-step explanation:
Given that,
The length of the ribbon is 4.5 m
Each piece is 15 cm long
We know that, 1 m = 100 cm
⇒ 4.5 m = 450 cm
Let there are n pieces. It can be calculated by dividing total length and each of each piece as follows :
There are 30 pieces.
r=d/2. r=17/2. r=8.5
Area= pi r^2. A= 3.14*(8.5)^2
A= 226.87
The decimal for 1 3/5 would be 1.6
The required expression is 100 - 0.2w
Step-by-step explanation:
Given,
Amount of radioactive substance = 100 mg
The substance decreases by 20% each week.
To find the remaining amount of the in w weeks.
Now,
Each week 20% = 0.2 of the substance will be decreased.
So, in w weeks 0.2×w of the the substance will be decreased.
Hence,
The remaining substance = 100 - 0.2w
