I think 14 are produced because if you go up by that you get it
Answer:

Explanation:
Given that:
Half life = 30 min
Where, k is rate constant
So,
The rate constant, k = 0.0231 min⁻¹
Using integrated rate law for first order kinetics as:
Where,
is the concentration at time t
is the initial concentration
Given that:
The rate constant, k = 0.0231 min⁻¹
Initial concentration
= 7.50 mg
Final concentration
= 0.25 mg
Time = ?
Applying in the above equation, we get that:-

Weathering<span> breaks down and loosens the surface minerals of rock so they can be transported away by agents of erosion such as water, wind and ice. There are </span>two types<span> of </span>weathering<span>: </span>mechanical<span> and </span>chemical<span>. </span>Mechanical weathering<span> is the disintegration of rock into smaller and smaller fragments.</span>