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
Your answer would be D. 225%. 9/4 equals to 2.25 which multiplied but a 100 to make the percentage equals 225%.
Step-by-step explanation:
a =45°
b=45°
c=30°
d=30°
e=30°
f=30°
total of the angle
90×4=360
Answer: her call lasted for 44 minutes
Step-by-step explanation:
Linda purchase a prepaid phone card for $30. This means that the credit on her card is $30.
Long distance calls cost $0.17 each. Linda use her card only to make a long distance call. Assuming she made a total of x minutes of long distance calls, the cost would be $0.17x. The amount remaining on her card will be
30 - 0.17x
if the remaining credit on her card is $22.52, the number of minutes,x that the call lasted will be
22.52 = 30 - 0.17x
0.17x = 30 - 22.52
0.17x = 7.48
x = 7.48/0.17 = 44
