MathDB

24

Part of 1962 AMC 12/AHSME

Problems(1)

Three Machines

Source:

3/3/2010
Three machines P, Q, and R, \text{P, Q, and R,} working together, can do a job in x x hours. When working alone, P \text{P} needs an additional 6 6 hours to do the job; Q \text{Q}, one additional hour; and R R, x x additional hours. The value of x x is: <spanclass=′latex−bold′>(A)</span> 23<spanclass=′latex−bold′>(B)</span> 1112<spanclass=′latex−bold′>(C)</span> 32<spanclass=′latex−bold′>(D)</span> 2<spanclass=′latex−bold′>(E)</span> 3 <span class='latex-bold'>(A)</span>\ \frac23 \qquad <span class='latex-bold'>(B)</span>\ \frac{11}{12} \qquad <span class='latex-bold'>(C)</span>\ \frac32 \qquad <span class='latex-bold'>(D)</span>\ 2 \qquad <span class='latex-bold'>(E)</span>\ 3