2021年必威体育精装版美国数学竞赛 AMC 10A （学习版）.pdfVIP

批注[c1]: 2021 AMC 10A Problem 1 What is the value of Solution 1 Problem 2 Portias high school has times as many students as Laras high school. The two high schools have a total of students. How many students does Portias high school have? Solution 1 Problem 3 The sum of two natural numbers is . One of the two numbers is divisible by . If the units digit of that number is erased, the other number is obtained. What is the difference of these two numbers? Solution 1 1 / 11 Problem 4 A cart rolls down a hill, travelling inches the first second and accelerating so that during each successive -second time interval, it travels inches more than during the previous -second interval. The cart takes seconds to reach the bottom of the hill. How far, in inches, does it travel? Solution 1 (Arithmetic Series) Problem 5 The quiz scores of a class with students have a mean of . The mean of a collection of of these quiz scores is . What is the mean of the remaining quiz scores of terms of ? Solution 1 (Generalized) Problem 6 Chantal and Jean start hiking from a trailhead toward a fire tower. Jean is wearing a heavy backpack and walks slower. Chantal starts walking at miles per hour. Halfway to the tower, the trail becomes really steep, and Chantal slows down to miles per hour. After reaching the tower, she immediately turns around and descends the steep part of the trail at miles per hour. She meets Jean at the halfway point. What was Jeans average speed, in miles per hour, until they meet? Solution 1 (Generalized Distance) 2 / 11 Problem 7 Tom has a collection of snakes, of which are purple and of which are happy. He observes that all of his happy snakes can add, none of his purple snakes can subtract, and all of his snakes that cant subtract also cant add. Which of