Question

There are 108 flights from an airport, 20 of which are longer than 3 hours. The flight from this airport will be randomly chosen. What is the probability it is longer than 3 hours? Enter your answer as a fraction, in simplest form, in the box.

Answer 1

20 / 108 reduces to 5/27

Answer 2

Integer numbers prime factorization: 
20 = 22 * 5; 
 108 = 22 * 33;Take all the common prime factors, by the lowest powers.Greatest (highest) common factor (divisor), gcf, gcd: 
gcf, gcd (20; 108) = 22 = 4;Step 2: Divide fraction's both numerator and denominator by their greatest common factor (divisor), gcf (gcd)