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