This is just another way of asking "what is the volume of a sphere of 6cm"
The volume of a sphere is

The R is 3cm in this problem since the diameter is twice the radius. For a 3cm radius sphere this is 113.1cm^3
Answer:
The percentage of overdue accounts are held by customers in the "risky credit" category is 62.5%
Step-by-step explanation:
Customers in the "risky" category (25% of total accounts) allow their accounts to go overdue 50% of the time on average.
That means that on average, 12.5% of total accounts is overdue.
0.25*0.50 = 0.125
In the "good credit" category only 10% goes overdue. That means 7,5% of total accounts goes overdue in this category.
0.75*0.10=0.075
The total accounts that go overdue is 0.125+0.075 = 0.200.
The percentage of overdue accounts held by customers in the "risky credit" category is:
0.125/0.200 = 0.625 or 62.5%
The right triangle is 120 degrees
The third equation is the correct one. After 100 years, about 115 grams will remain.