Question

Vaibhav was writing the CAT exam. There were
four passages of equal length (in words) and
they had 5, 8, 8 and 6 questions respectively.
Vaibhav can answer exactly 12 questions in
the time he takes to read any one of the four
passages. Assume that his rate of reading
and answering question remains the same
across all four passages. By what rate should
Vaibhav increase his reading speed in order
to cutdown his total time spent by 10%?
(1) 20%
(2) 18.5%
(3) 25%
(4) 9.8%​

Answer 1

Answer:

20

Step-by-step explanation:

I will be there at the same time

Answer 2

Answer:

Step-by-step explanation:

Let time taken to answer a question = t

                 Ist    IInd     IIIrd    IVth

Read         12t   12t      12t       12t      → 48t

Q’s            5t     8t       8t        6t        → 27t

Total         17t    20t     20t      18t      → 75t

Total time = 75t

10% less = 67.5t

⇒ Time spent on only reading all 4 passages

= 67.5t – 27t = 40.5t

∴ Each passage requires =

40.5/4  = 10.125t

He has to increase his speed by

12t/ 10.125t = 1.185

Increase in speed = 1.185 – 1 = 0.185 i.e. 18.5%