Each morning of her five-day workweek, Jane boughteither a 50-cent muffin or a 75-cent bagel. Her totalcost for the week was a whole number of dollars. Howmany bagels did she buy?(A)1(B)2(C)3(D)4(E)52009 AMC 10 B, Problem #1—2009 AMC 12 B, Problem #1—“Make a table for the cost of the muffins and bagels.”Difficulty:Medium-easyNCTM Standard:Number and Operations Standard:compute fluently and make reasonableestimates.Mathworld.comClassification:NumberTheory>Arithmetic>GeneralArithmetic>
Which of the following is equal to13-1412-13?(A)14(B)13(C)12(D)23(E)342009 AMC 10 B, Problem #2—“The least common multiple of 2, 3, and 4 is 12.”SolutionAnswer (C):The least common multiple of 2, 3, and 4 is 12, and13-1412-13·1212=4-36-4=12.Difficulty:EasyNCTM Standard:Number and Operations Standard:judge the effects of such operations asmultiplication, division, and computing powers and roots on the magnitudes of quantities.Mathworld.comClassification:NumberTheory>NumberTheoreticFunctions>LeastCommon Multiple>Least Common Multiple
Paula the painter had just enough paint for 30identically sized rooms.Unfortunately, on the wayto work, three cans of paint fell off her truck, so shehad only enough paint for 25 rooms. How many cansof paint did she use for the 25 rooms?Difficulty:Medium-easyNCTMStandard:AlgorithmStandard:usesymbolicalgebratorepresentandexplainmathematical relationships.Mathworld.com Classification:Number Theory>Arithmetic>Fractions>Ratio
A rectangular yard contains two flower beds in theshape of congruent isosceles right triangles.Theremainder of the yard has a trapezoidal shape, asshown. The parallel sides of the trapezoid have lengths15 and 25 meters.What fraction of the yard isoccupied by the flower beds?