Sixth grade mathematics Olympiad! Urgent! 1. My mother bought some apples. She ate 1 / 3 and 1 / 3 apples on the first day, left 1 / 4 and 1 / 4 apples on the second day and left 1 / 3 and 1 / 3 apples on the third day. How many apples did she buy 2. In a school, the fourth grade is 25% more than the third grade, the fifth grade is 10% less than the fourth grade, and the sixth grade is 10% more than the fifth grade. If the sixth grade has 38 more people than the third grade, how many people are there in the third, fourth, fifth and sixth grades? 3. Vehicle a and vehicle B leave from ab at the same time. After meeting, vehicle B arrives at a in 5 hours. However, vehicle a exceeds B by 90km, 25% of the whole journey

Sixth grade mathematics Olympiad! Urgent! 1. My mother bought some apples. She ate 1 / 3 and 1 / 3 apples on the first day, left 1 / 4 and 1 / 4 apples on the second day and left 1 / 3 and 1 / 3 apples on the third day. How many apples did she buy 2. In a school, the fourth grade is 25% more than the third grade, the fifth grade is 10% less than the fourth grade, and the sixth grade is 10% more than the fifth grade. If the sixth grade has 38 more people than the third grade, how many people are there in the third, fourth, fifth and sixth grades? 3. Vehicle a and vehicle B leave from ab at the same time. After meeting, vehicle B arrives at a in 5 hours. However, vehicle a exceeds B by 90km, 25% of the whole journey

1. How many students are left? How else do you want to do? Let's set the third grade students as X. The result is: x + 38 = (1 + 0.25) * (1-0.1) * (1 + 0.1) x 1.25 * 0.9 * 1.1x-x = 38 0.2375x = 38 x = 160. So: the number of third grade students = 160, the number of fourth grade students = 160 * 1.25 = 200, the number of fifth grade students = 200 * 0.9 = 180, the number of sixth grade students = 1