Bunuel wrote:
SOLUTION
A citrus fruit grower receives $15 for each crate of oranges shipped and $18 for each crate of grapefruit shipped. How many crates of oranges did the grower ship last week?
Let x be the # of oranges and y the # of grapefruits. Note that, both x and y must be integers.
Question: x=?
(1) Last week the number of crates of oranges that the grower shipped was 20 more than twice the number of crates of grapefruit shipped --> x=2y+20. Not sufficient to calculate x
(2) Last week the grower received a total of $38,700 from the crates of oranges and grapefruit shipped --> 15x+18y=38700 --> 5x+6y=12900. Multiple values are possible, for istance: x=180 and y=2000 OR x=60 and y=2100.
(1)+(2) We have two distinct linear equation with two unknowns, hence we can solve for x and y. Sufficient.
Answer: C.
Hi Bunnel,
I marked this one as B, as i thought that by prime factorization we can get the number of multiples of 15 and 18.
However i later did the prime factorization and now know that their is no way of knowing how many times 15 or 18 goes in to 38,700.
I remembered this technique as I had used it in Problem Solving, so want to know whether this technique can be used in DS questions.