12. Every c teaspoons of a particular multiple vitamin, in granular form, contains 0.65 the minimum daily requirement of vitamin C. How many teaspoons of this vitamin are required to supply 1.25 the minimum daily requirement? 13. Write the ratio 16 to 100 as a percent. 14. Convert - to a percent. 15. On a 45 questions exam, a student gets 40%. How many questions did this student get correct? 16. A vitamin tablet, which weighs 250 milligrams, contains 35 milligrams of vitamin C. What percent of the weight of this tablet is vitamin C? 17. Five years ago, a secretary made $11,200 annually. The secretary now makes $17,920 annually. By what percent has this secretary's salary been increased? 18. A typist was able to increase his speed by 120% to 42 words per minute. What was her original typing speed? 19. A salesperson makes a commission of 12% on the total amount of each sale. If, in one month, she makes a total of $8,520 in sales, how much has she made in commission? 20. A salesperson receives a salary of $850 per month plus a commission of 85 % of her sales. If, in a ticular mor she sells $22 800 worth of merchandise what will be her monthly earnings