-5x+3y>9 help me plesese

Ricardo ran the 400 meter race 3 times his fastest time was 54.3 seconds his slowest time was 56.1 seconds if his average time was 55.0 seconds what was his time for the third race

Credit card a offers an introductory apr of 3.4% for the first three months and standard apr of 15.7% thereafter,

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81