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PREP07 Test 1
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If a equals the sum of the even integers from 2 to 20, inclusive, and b equals the sum of the odd integers from 1 to 19, inclusive, what is the value of a - b ?
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PREP07 Test 1
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Machine A, working alone at its constant rate, manufactures 280 bolts per hour, and machine B, working alone at its constant rate, manufactures 220 bolts per hour. How many hours will it take for machines A and B, working together at their respective constant rates,to manufacture 1,000 bolts?
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PREP07 Test 1
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Three boxes of supplies have an average (arithmetic mean) weight of 7 kilograms and a median weight of 9 kilograms. What is the maximum possible weight, in kilograms, of the lightest box?
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OG17 OG18
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For each positive integer n, the quantity $$s_n$$ is defined such that $$s_{n+2} = {s_n}^2 - s_{n+1}$$. In addition, $$s_2 = 1$$.In the table, select values for $$s_1 $$ and $$s_4 $$ that are jointly compatible with these conditions. Select only two values, one in each column.
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PREP07 Test 2
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If $$(400)(6,000) = (240)(100^x)$$, what is the value of x ?
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Manhattan
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If n divided by 7 has a remainder of 2, what is the remainder when 3 times n is divided by 7?
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Manhattan
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In a group of 9 children, there are twice as many girls as boys, and twice as many right-handed people as there are left-handed people. If a third of the boys are left-handed, how many girls are right-handed?
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Manhattan
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If r and p are two different prime numbers, which of the following is the smallest possible value of r + p?
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300难题
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Let n and k be positive integers with $$ k\leq n$$. From an n * n array of dots, a k * k array of dots is selected. The figure above shows two examples where the selected k * k array is enclosed in a square. How many pairs (n,k) are possible so that exactly 48 of the dots in the n * n array are NOT in the selected k * k array?
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[test] - test - test - test - The outer dimensions of a closed rectangular cardboard box are 8 centimeters by 10 centimeters by 12 centimeters, and the six sides of the box are uniformly $$\frac{1}{2}$$ centimeter thick.
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[test2] - The outer dimensions of a closed rectangular cardboard box are 8 centimeters by 10 centimeters by 12 centimeters, and the six sides of the box are uniformly $$\frac{1}{2}$$
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181215
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The area of the circular mirror is 64π. A circular edge will be inserted on the mirror. The area of the circular edge is 17π. What is the width of the edge?
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181215
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AB=3, BC=4. AD=DE, ∠ADB=∠ABC=90°,CE=?
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181215
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$$(x+y)^{2}$$=13,$$(x-y)^{2}$$=5, xy=?
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190124
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A six-digit number is composed of 54X, Y, and 18. X and Y could be 3,5,8 and X and Y can be equal. How many cases are there in which 8 is a factor of this six-digit number?
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190113 还原机经选题: 文字题&几何
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There are three programs in one ceremony: violin performance, piano performance, and trumpet performance. In each performance, two students will respectively perform on the same instrument in order. A and B can only play the violin, C and D can only play the piano, and E and F can only play the trumpet. How many different appearance orders?
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190124
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500 students chose courses. Students who didn't take a single course accounted for 1% of the total. Students who took 1, 2, 3 and 4 courses accounted for 50%, 30%, 10% and 9% of the total number of students respectively. What is the median of the number of the courses the students chose?
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190124
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AB=9, BC=4. A,B,C are not collinear. Which of the following may be the distance of AC?
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190124
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x comes from the set {-3,-2,-1,2,3}. How many different results can be achieved by substitute the possible value of x into the algebraic expression -|$$x^{2}$$-1|?
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190321
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What's the remainder of $$10^{98}-1$$ when divided by 11?
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