Answer:
Quantity remaining= 27.5 grams
Step-by-step explanation:
If the initial quantity of the radioactive isotope= 220 grams
And for each half life it will reduce to half of its original quantity
For first half life
Quantity= 220/2
Quantity= 110 grams
Now for the second half life , the quantity to work with will be 110 grams
Second half life
Quantity= 110/2
Quantity= 55 grams
For the third half life , the quantity to work with is 55 grams
Third half life
Quantity= 55/2
Quantity= 27.5 grams
So after 3 half life's of this radioactive isotope, the amount remaining out of 220 = 27.5 grams.
Another simple way to do this
Since half life reduce the isotope by half of its original.
The third half life will reduce it by (1/2)^3= 1/8
So the quantity remaining= 1/8*220
Quantity remaining= 27.5 grams
Answer:
75 coloured pencils
Step-by-step explanation:
Let's say Jordon has x total pencils.
We know that 20% of these x pencils is 15, so we have:
20% * x = 15
Remember that % is just "out of 100", so 20% = 20/100 = 0.20. Then:
0.20x = 15
x = 15 / 0.20 = 75
Jordon has 75 coloured pencils.
Answer:
m =
8 - 4
6 - 3
=
4
3
d = √(6 - 3)2 + (8 - 4)2 = 5
4
3
= tan(θ)
θ = tan-1(
4
3
) = 53.13°
Step-by-step explanation:
Answer:
11
Step-by-step explanation:
Unknown number = x
If twice the difference of x and 8 is 6:
2(x-8) = 6
2x-16 = 6
2x = 6 + 16
2x = 22
x = 22/2
x = 11
Answer from Gauthmath
Answer:
I cant answer it because you cant copy it it doesnt allow me