Runoff (Hope this helped)
given days = 42 days
So, number of half life, n = 42/14.3 = 2.93
So, after 42 days, the mass of sodium phosphate sample left = original mass
x (1/2)^n,
= 157 mg x (1/2)^2.93 = 20.60 g of Na3PO4 after 42 days
Formula mass of Sodium phosphate = 3(23) + 32 + 4(16) amu = 165 amu
165 g of sodium phosphate contains 32 g of Phosphorus
20.60 g ------------------------------? = 20.60 x 32/ 165 =3.99g of P32
Answer : The distance covered by slow snail in 24 hours is 
Explanation :
As we are given that the a slow snail can travel 2.2 cm in 1 minute. Now we have to calculate the distance covered by slow snail in 24 hours.
First we have to convert 24 hours in minutes.
Conversion used : (1 hour = 60 minutes)
As, 1 hour = 60 minutes
So, 24 hour = 24 × 60 minutes
= 1440 minutes
Now we have to calculate the distance covered by slow snail in 24 hours.
In 1 minute, the distance covered by slow snail = 2.2 cm
In 1440 minute, the distance covered by slow snail = 1440 × 2.2 cm
= 3168 cm
= 
Now we have to convert 'cm' into 'pm'.
Conversion used : 
As, 
So, 
Therefore, the distance covered by slow snail in 24 hours is 