A machine, working at a constant rate, manufactures 18 dies in 25 minutes. How many dies does it make in 1 hr 15 min? Choose the correct choice from the following: A) 55 B) 53 C) 54 D) 52 E) 50

Rationale: "change 1 hr 15 min to 75 min . for this , we need to set up a simple proportion of dies per time 18 / 25 = s / 75 the absolutely worst thing you could do at this point in the problem is to cross - multiply . that would be a supremely unstrategic move . we can cancel the common factor of 25 in the two denominators . 18 / 1 = s / 3 s = 3 * 18 s = 54 the machine would be 54 dies in 1 hr 15 min . answer : c"
Answer: C