The GCD of two numbers is 19 and their LCM is 285. One of the numbers is 57. Find the other number.
The problem provides the greatest common divisor (GCD) and the least common multiple (LCM) of two numbers, and one of those numbers, say \(A = 57\). We are asked to find the other number, \(B\). The key relationship between two numbers \(A\) and \(B\), their GCD, and their LCM is given by the formula:
\[A \times B = \gcd(A, B) \times \text{lcm}(A, B)\]
We are given:
\(\gcd(A, B) = 19\)
\(\text{lcm}(A, B) = 285\)
\(A = 57\)
Substitute the given values into the relationship formula:
\[57 \times B = 19 \times 285\]
To find \(B\), we isolate it by dividing both sides of the equation by \(57\):
\[B = \frac{19 \times 285}{57}\]
We can simplify this calculation by noting that \(57 = 3 \times 19\):
\[B = \frac{19 \times 285}{3 \times 19} = \frac{285}{3}\]
Performing the final division, we get:
\[B = 95\]
We have found that the other number is \(95\). To verify, we can check the GCD and LCM of \(57\) and \(95\):
The values match the original data, confirming the result. Thus, the other number is \(\boxed{95}\).
In logistics, finding the greatest common divisor and least common multiple is essential for coordinating schedules. For example, if two delivery trucks are on different routes—one returning every 57 minutes and another every 95 minutes—understanding how these cycles interact helps managers schedule maintenance or rest periods so they occur simultaneously. By knowing the GCD is \(\text{gcd}(57, 95) = 19\) and the LCM is \(\text{lcm}(57, 95) = 285\), the manager can plan for the trucks to meet at the depot every 285 minutes, ensuring operational efficiency.