Two identical machines have the ability to produce both nuts and bolts. However, it takes 1 second to produce a bolt but 2 seconds to produce a nut. What is the fastest the two machines, working together, can produce 1,800 nuts and 1,800 bolts?
Pick one.
A) 1,250 seconds  B) 1,500 seconds  C) 1,750 seconds  D) 2,700 seconds  E) 3,000 seconds
I used the Rate formula (R=\frac{1}{T})   Rate of 1st machine = Rate of making 1 bolt + Rate of making 1 nut = 1 + \frac{1}{2}   Rate of 1st machine = Rate of 2nd machine   After this I got lost.   Please can you help how to approach using algebra?   I wouldn't complicate:   1 machine needs 1,800*1 seconds to produce 1,800 bolts, so 2 need half of that, so 1,800/2 seconds.=900   1 machine needs 1,800*2 seconds to produce 1,800 nuts, so 2 need half of that, so 1,800*2/2 seconds.=1800   total =2700 sec   2,700 seconds
<result>D</result>
Two identical machines have the ability to produce both nuts and bolts. However, it takes 1 second to produce a bolt but 2 seconds to produce a nut. What is the fastest the two machines, working together, can produce 1,800 nuts and 1,800 bolts?