My attempt.

2. According to the directions on a can of frozen orange juice concentrate, 1 can of concentrate is to be mixed with 3 cans of water to make orange juice. How many 12 ounce cans of the concentrate are required to prepare 200 6 ounce servings of orange juice?

a) 25 b)34 c)50 d)67 e)100

Let us assume the base to be a 6 ounce cup.

Orange juice is a ratio of 1:3 (Concentrate: Water)

To prepare a 200 servings of juice we require 50 units (6 ounces) of concentrate and 150 units of water.

Hence 50 units (6 ounces) of concentrate => 25 units (12 ounces) of concentrate.

Answer: A

-----------------------------------------------------------------------------------------------------------------------Data sufficiency

3. At certain pet shop, 1/3 of the pets are dogs and 1/5 of the pets are birds. How many of the pets are dogs?

A. there are 30 birds at the pets shop

B. There are 20 more dogs at the pets shop

Solution:

Statement A:

1/5th of the pets are birds corresponds to the 30 birds. Hence the total number of pets is 150.

1/3rd of the pets are dogs => 1/3rd of150 => 50 dogs.

Statement A is sufficient.

Statement B:

Here I am not sure of whether to read the statement in relation with only the two kinds of pets (dogs and birds) or to read it as it is, without any relation.

Assuming that the statement reads like "There are 20 more dogs (than birds) at the pets shop" and proceeding further....

With the ratio of dogs and birds as 1/3: 1/5 => 5x:3x

Hence 5x-3x = 20

x=20 Hence number of dogs is 50.

Answer: D

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4. Did it take Pei more than 2 hrs to walk a distance of 10miles along a certain trail (1 mile =1.6km)

A. Pei walked this distance at an average rate of less than 6.4 kilometer per hours

B. On average, it took Pei more than 9 minutes per kilometer to walk this distance.

Solution:

Make all the units common and hence 10 mile => 16 km.

Statement A:

If Pei walked at a rate of 6.4 km/hr she would have taken more than 2 hours and since she walked slower than 6.4 km/hr she would have taken more than 2 hours.

Sufficient.

Statement B:

In order for Pei to have covered the distance of 16 km she should have covered at least 2 km per 15 minutes. With statement B, if Pei took exactly 9 mins per km then she would have covered 2 km every 18 minutes.

Since she took more than 9 min per km she would have definitely taken more than 2 hours to cover the 16 km.

Sufficient.

Answer: D

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@ kilukilam

Kindly post the correct answer.

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