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.
_________________