vivatran wrote:

A software programmer does 20% of the work in 80% of the time, and 80% of the work in the remaining 20% of the time. If the code he writes is X lines long and he was given one month (30 days) to accomplish the task, then, assuming that the programmer works at a constant rate in each of the two stages, How many lines of code were written in the last two weeks, in terms of X?

A. 13x /15

B. 15x/15

C. 7x/15

D. 2x/30

E. 13x/30

I had the same approach as

VeritasPrepKarishma had.

we can easily eliminate B, C, D, and E right away.

in the last 6 days, he did 80% of the job. therefore, in last 2 weeks, he finished more than 80% of the work.

B = X, or 100% - CLEARLY not

C = slightly more than 50%. 9x/15 = 3x/5 = 60%. but this is way more than 7x/15

D = way too small

E = way too small

now..to verify

we know that in first 24 days, he did x/5 work. each day, he did x/120 work. in 8 days, he did 8x/120 work, or 4x/60 or x/15.

in last 6 days, he did 4x/5 work.

total work done in last 2 weeks:

4x/5 + x/15

multiply first one by 3:

12x/15 + x/15 = 13x/15

answer is A.

I believe it should be a sub-600 level question, if the answer choices are not changed so that to not eliminate incorrect ones so easy.