So, in this question, you've got three different machine types all working together, and you need to figure out exactly how many machines are running. Let's break this down step by step.
Understanding What We're Looking ForYou need to find the
total number of machines working. Here's what we know:
- Type A: fills 400 cans/minute
- Type B: fills 600 cans/minute
- Type C: installs 2,400 lids/minute
The key constraint that many students miss:
Every filled can gets exactly one lid. This means:
\(\text{Number of cans filled} = \text{Number of lids installed}\)
Analyzing Statement (1)"A total of 4,800 cans are filled that minute"Let's think about this... We know the total production, but not how it's distributed. Notice how we could achieve 4,800 cans in different ways:
- Using only Type A machines: \(12 \times 400 = 4,800\) cans
→ Need 2 Type C machines for lids: \(2 \times 2,400 = 4,800\) lids
→ Total: 12 + 0 + 2 =
14 machines- Using only Type B machines: \(8 \times 600 = 4,800\) cans
→ Still need 2 Type C machines
→ Total: 0 + 8 + 2 =
10 machinesSince we get different totals, Statement (1) is
NOT sufficient.
Analyzing Statement (2)"There are 2 Type B machines for every Type C machine"Here's what you need to see - this gives us a ratio \(B = 2C\), but without knowing the actual number of C machines, we can't pin down the total. The ratio could scale up or down while maintaining the 2:1 relationship.
Statement (2) alone is
NOT sufficient.
Combining Both StatementsNow here's where it gets interesting! When you combine both statements:
From Statement 1: We need exactly 4,800 lids for 4,800 cans
→ Number of Type C machines: \(\frac{4,800}{2,400} = 2\) machines
From Statement 2 with C = 2:
→ Type B machines: \(2 \times 2 = 4\) machines
Type B produces: \(4 \times 600 = 2,400\) cans
Remaining cans needed: \(4,800 - 2,400 = 2,400\)
Type A machines: \(\frac{2,400}{400} = 6\) machines
Total: 6 + 4 + 2 =
12 machinesAnswer: C - Both statements together are sufficient, but neither alone is sufficient.
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You can check out the
step-by-step solution on Neuron by e-GMAT to master the systematic framework for solving production balance problems quickly. You can also explore other GMAT official questions with detailed solutions on Neuron for structured practice
here - they show you exactly how to spot the patterns that save time on test day!