Matt and Jaron are constructing a brick wall. If they work together, each at his own constant rate, how many hours does it take for them to finish the wall?

(1) Matt lays 3 bricks for every 2 that Jaron lays --> the ratio of the rates is 3 to 2. Not sufficient.

(2) There are 1000 bricks in the wall. Clearly insufficient.

(1)+(2) If Matt and Jaron lay 3 and 2 bricks respectively in 1 second the answer would be 200 seconds but if Matt and Jaron lay 3 and 2 bricks respectively in 1 hour the answer would be 200 hours. Not sufficient.

Answer: E.
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The question asks "how many hours" does it take to finish the wall?"

1) Ratio of bricks laid M:J = 3:2
Nothing here about hours.
Insufficient

2) 1000 total bricks
Nothing here about hours.
Insufficient

Together:
Ratio of bricks laid + total bricks
Still nothing about hours.
Insufficient

Answer: E

t1000

Can you explain how (1) just gives us the ratio of rates?

Basically what (1) says is that in the same time period Matt lays 3 bricks while Jaron lays 2 bricks, thus the ratio of the rates is 3 to 2.
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We need to determine how many hours it will take for Matt and Jaron to construct a wall.

Statement One Alone:

Matt lays 3 bricks for every 2 that Jaron lays.

Since we cannot fully determine the rate of Matt or Jaron, and since we do not know how many bricks make up the wall, statement one is not sufficient to answer the question.

Statement Two Alone:

There are 1000 bricks in the wall.

Since we do not have the rates of either Matt or Jaron, statement two is not sufficient to answer the question.

Statements One and Two Together:

Using the information in statements one and two, we still cannot answer the question.

If Matt’s rate was 3 bricks per hour and Jaron’s was 2 per hour, then it would take 1,000/5 = 200 hours to complete the job. However, if Matt’s rate was 6 bricks per hour and Jaron’s was 4 per hour, then it would take 1,000/10 = 100 hours to complete the job.

Answer: E
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