Answer:

Step-by-step explanation:
we are given half-life of PO-210 and the initial mass
we want to figure out the remaining mass <u>after</u><u> </u><u>4</u><u>2</u><u>0</u><u> </u><u>days</u><u> </u>
in order to solve so we can consider the half-life formula given by

where:
- f(t) is the remaining quantity of a substance after time t has elapsed.
- a is the initial quantity of this substance.
- T is the half-life
since it halves every 140 days our T is 140 and t is 420. as the initial mass of the sample is 5 our a is 5
thus substitute:

reduce fraction:

By using calculator we acquire:

hence, the remaining sample after 420 days is 0.625 kg
Step-by-step explanation:
Ethan sold 2/3 gallon of lemonade.
Kayla sold some lemonade too.
Together they sold 1 1/4 gallons.
Subtract 2/3 from 1 1/4 as follows :

So, Kayla sold 7/12 gallons of lemonade.
As 2/3 is more than 7/12, it means Ethan sold more lemonade.

It means Eathn sold 1/12 more lemonade.
Answer:
Step-by-step explanation:
Qualitative:
Eye colour
Grade level
favourite music group
Quantitive:
Capacity in litres
Height in inches
Number of siblings
8 foot path
1st step = 8/2 = 4ft
2nd step = 4/2 = 2ft
3rd step = 2/2 = 1ft
4th step = 1/2 = 1/2ft
So he covered 7 1/2 ft (or 7.5ft)