happy1992 wrote:
If Vivica typed a document at an average rate that was greater than 90 words per minute, did it take her less than one hour to type this
document?
(1) Vivica typed the Örst three-quarters of the words in the
document in 42 minutes.
(2) Vivicaís rate of words per minute was constant for the
Duration of the document.
Solution:
Givent that, average speed is = Vav > 90 words/min
and time < 1 hour or t < 60 min
1) 3/4 of document is done in 42 min
means 1/4 remaining.
if we assume the work will finish in 60 minutes, then 3/4 of 60 =45 minutes : so 42 is less than 45
but we are not sure of speed of remaining 1/4 . Not sufficient
2) speed throughout is constant. NOT SUFFICIENT
Combining 1&2,
the speed for remaing 1/4 document :
3/4 ----- 42 min
1/4------ 42/3 = 14 min
total time it will take = 42 +14 =56 min, which is less than 60 min
So, Answer is C
Kudos, if its helpful