A first-order reaction is 45% complete at the end of 33 minutes. What is the length of the half-life of this reaction

Light travels through space at 186,282 miles per second and it takes about 1.3 seconds for light to travel from the moon to earth. which of the following is the correct method of finding the distance, in miles, between the moon and earth? add 186,282 and 1.3 divide 186,282 by 1.3 multiply 186,282 by 1.3 subtract 1.3 from 186,282