Answer:
See explanation
Step-by-step explanation:
<u>Part A:</u> If Cole eats 3 bananas each day. These 3 bananas contain
mg of iron.
Let x be the number of vitamins Cole takes. Each whole vitamin contains 4 mg of iron, then x vitamins contain 4x mg of iron.
The total amount of iron Cole takes is

Cole needs to include at least 11 mg and at most 22 mg of iron in his diet each day, so

Solve it:

The smallest number of vitamins - 3, the greatest number of vitamins - 5.
<u>Part B: </u>Cole continues to eat 3 bananas each day. He pays
for bananas per week.
If Cole spends a total of $20 on bananas and vitamins this week, then he spent $20 - $14 = $6 on vitamins.
Let x be the number of vitamins Cole takes this week.
First 10 vitamins are free, then x - 10 vitamins each cost $0.50 (he pays an additional dollar for every 2 additional vitamins he purchases) and they cost

This amount of money is exactly $6, so

This means Cole takes 3 vitamins per day (the whole number) and he is able to meet his iron requirement every day this week, based on answer in Part A.