Help me with 15-28 please

Uanita borrowed $600 to purchase a new computer. she was charged 7% interest for two years. she used the simple interest formula to find the interest. i = 600(7)(2) what error did juanita make and how will her error affect the interest she calculates? explain.

Apatient is to take 60 mg of an antibiotic on day 1, take 45mg on days 2 and 3, take 30mg on days 4 and 5 and take 15 mg on days 6 and 7. how many total mg will the patient take?

You wanted to draw an enlargement of design that printed on a card that is 4 in by 5