Haeun bought 43 books and 20 toys from the market. If the price of each book and toy is ₩ 47 and ₩ 69 respectively, how much money did Haeun pay for the books?

The table below shows the number of pencils needed for different number of students. If each student should get same number of pencils, how many pencils are needed for 12 students?

Hyeonwoo's income is 20% less than Yoonsuh's income, Woojin's income is 40% less than Hyeonwoo's income, and Hyeonjoon's income is 20% less than Hyeonwoo's income. If Yoonsuh gave 40% of his income to Woojin and 60% of his income to Hyeonjoon, Woojin's new income would be what fraction of Hyeonjoon's new income?

Two walls of a an Indoor Stadium have to be painted. The first wall is of length 17 meters and height 8 meters. The cost of the paint for this wall is ₩20 per square meter. The second wall is of length 17 meters and height 9 meters. The cost of the paint for this wall is ₩30 per square meters. The ratio of the costs of painting the first wall to the second one is: