Help primary school mathematics to pursue practical problems

Help primary school mathematics to pursue practical problems

When father and son go on an outing, the father asks his son to take ten steps first, and then the father pursues them. It is known that when father takes three steps, the son can take five steps, while when father takes nine steps, the son has to take 17 steps. How many steps can father take to catch up with his son?
Answer: when father takes three steps, son can take five steps. So we can know that when father takes nine steps, son takes 15 steps. When father takes nine steps, son takes 17 steps, that is, when father takes nine steps, son takes 17 steps. 10 / (17-15) = 55 * 9 = 45, so it takes 45 steps to dare son

Uncle Wang loaned 100000 yuan to buy a car for transportation, with an annual interest rate of 5.49%. He plans to pay off the loan and interest in three years. His average monthly freight income from carrying goods by car is 7000 yuan, including three expenses: 10% of the freight income from fuel, 20% of the freight income from repair, road maintenance and tax, 1.1 million yuan of the driver's monthly salary, and the rest is the profit Can you pay off the loan and interest

Three year principal and interest: 10 + 10 × 5.49% × 3, = 10 + 1.647, = 11.647 (ten thousand yuan); three year profit: [0.7 × (1-10% - 20%) - 110] × 12 × 3, = [0.7 × 0.7-0.1] × 36, = 0.39 × 36, = 14.04 (ten thousand yuan); 140.4 thousand yuan ＞ 11.647 million yuan; answer: three year profit can repay the loan and interest

According to Haikou evening news, Yingli group's current production capacity is 800 MW, which is expected to increase by 50% after 2010, of which more than 90% will be sold to Europe and the United States. According to this calculation, how many MW will Yingli group's production capacity be sold to Europe and the United States after 2010
Please use the method of primary school to calculate the problem

Production capacity in 2010: 800 * (1 + 50%) = 1200, 90% sold to Europe and America, 1200 * 0.9 = 1080