可汗学院
46.A popular candy is manufactured to weigh 0.16 ounces per piece. The pieces are sold in packages of 36. If the allowable amount of variation in weight for one piece of candy is 0.03 ounces, which of the following equations can be used to determine the highest and lowest allowable weight, w, of a package of 36 pieces? Assume that the weight of the packaging is negligible.
47.Uche is a cartographer. He picks a scale to fit a map of India onto a page of an atlas. The page is 12 by 12 inches, with 0.75 inch margins on all 4 sides. India measures 3,214 kilometers from north to south and 2,933 kilometers from west to east. Uche wants the longest dimension of India to fit exactly in between the margins of the page. If k is the number of kilometers per inch in Uche's scale, which equation best models the situation?
48.Alma and Erika work part time stocking shelves at a grocery store. At 7:00 a.m. on Saturday, Alma begins unpacking boxes at a rate of 1 box every 6 minutes. Erika joins her at 7:45 a.m. and unpacks 1 box every 5 minutes. When finished with this task, a total of 24 boxes have been unpacked since 7:00 a.m. If x represents the number of minutes for which Alma has been working, which of the following equations best models the situation?
49.On a highway, drivers are required to maintain a speed of between 55 and 65 miles per hour (mph). A $7 penalty is assessed for each 1mph a driver’s speed is outside this range. If a driver receives a $42 penalty, what are possible values for his speed?
A.49 and 66mph
B.49 and 71mph
C.54 and 66mph
D.54 and 71mph
correct answer: B difficult degree: 4
53.Erika's times for the 1-mile run decreased consistently throughout her track season. She estimates that her time for the 1-mile run decreased by about 15 seconds (secs) for every 2 weeks of training. If Erika ran a mile in 8 minutes (mins) and 20 secs at the start of the season, and x weeks into her training ran a mile in 7 mins and 5 secs, which of the following equations best models the situation?
A.500−7.5x=425
B.500−15x=425
C.500+7.5x=425
D.500+15x=425
correct answer: A difficult degree: 4
