BTGmoderatorLU wrote:Source: e-GMAT

The cost of each crate of milk is $40 and each crate of eggs is $25. If the seller sells at least one crate of each type every week and the number of crates sold is an integer find out how many crates of eggs did he sell last week?

1. Last week the seller sold eggs and milk worth $300.
2. The number of crates of eggs sold is one more than the number of crates of milk sold.

The OA is A

Say the number of crates of milk the seller bought is x and that of eggs is y.

Thus, the total cost = 40x + 25y. We have to get the value of y.

Let's take each statement one by one.

1. Last week the seller sold eggs and milk worth $300.

40x + 25y = 300
=> 8x + 5y = 60 => y = (60 - 8x)/5 = 12 - 8x/5

So, y = 12 - 8x/5

Since y is an integer, x must be a multiple of 5. If x = 5, y = 4. If x = 10, y = -4, a negative value (Invalid). Thus, the only possible value of y = 4. Sufficient.

2. The number of crates of eggs sold is one more than the number of crates of milk sold.

Certainly insufficient.

The correct answer: A

Hope this helps!

-Jay
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