16-17. What is 20% of 90 18-19. 12 out of 30 students studied Mathematics. What percent studied Mathematics? 20-21. In an electronics store a Php 75.00 earphone is labeled. Save 15 percent. What is the sale price of the earphone? 22-23 Sir Gab borrowed 3600 to finance his printer repair at a rate of 6.25 % for 4.75 years. How much interest did he pay ? 24-25. A computer salesman eans a 5.5 % commission on each sale. If he sells 5 computers in one week for a total of Php 15 500 How much commission does he earn?