Answer:
a) Two half lives, b) 
Step-by-step explanation:
a) The polonium-210 has a half life of 138.4 days. Therefore, 1.994 half lives have past.
b) Mass decay is described by the following exponential model:
The time constant for the isotope is:
The mass of the isotope after 276 days is:
3/8=0.375
2/5=0.4
0.38=0.38
0.375<0.38<0.4
therefore: 3/8,0.38,2/5
*Remember that you can convert fractions to decimals by dividing the numerator by the denominator! This makes it much easier to compare :)
Answer:
$144
Step-by-step explanation:
120$
12+12= $24
120+24= 144
170 cm. The unknown length on the left is 21 cm
the answer is 89
Step-by-step explanation:
it does not matter if the number is negative the absolute value is the number inside the lines
