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MATHEMATICS FOR AIR CREW TRAINEES 8 speed is 14 percent greater than the calibrated air speed. If the calibrated air speed is 172 mph, what is the true air speed? First solution: 14 percent=.14 .14X172 mph=24 mph Therefore 172 mph+24mph=196 mph Answer. Second solution: 114 percent=1.14 1.14X172 mph=196 mph Answer. (c) Example: At a certain altitude and temperature, the true air speed is 14 percent greater than the calibrated air speed. If the true air speed is 210 mph, what is the calibrated speed? Solution: Caution must be used in this type of problem. Percent increases as usually understood mean so many percent of the smaller number. Consequently, since 14 percent=.14, calibrated air speed+(.14)X(Calibrated air speed=210 mph Therefore (1.14) (calibrated air speed)=210 mph or calibrated air speed = (210 mph)/1,14 = 184 mph Answer. This kind of problem can be checked very easily. Since 14 percent of calibrated air speed=.14X184=26 mph, 14 percent of calibrated air+calibrated air speed=26 mph+184 mph=210 mph Check. (4) To change a common fraction to a percent, first change the fraction to a decimal and then change the decimal to a percent. (a) Example: Express 3/4 as a percent. Solution: 3/4=.75=75% (b) Example: Express 1/3 as a percent. Solution: 1/3=.333 . . .=33.33 . . .% or 33 1/3% Answer. (5) All types of percentage problems may easily be solved by the "equation: method. (a) Example: What is 65% of 220? Solution: x is 65% od 220 x=(.65)(220)' x=143 Answer. NOTE.-"Is: always stands for "equals." "Of" always stands for "times." In the equation the percent must be used in the decimal form. (b) Example: 250 is what percent of 900? Solution: 250=x . 900 x=250/900=.28=28% Answer. 509469°-43-3 17