Quantitative - Time and work

Quantitative - Time and work
Question:-
Option (A)
20 days
Option (B)
25 days
Option (C)
30 days
Option (D)
40 days
Correct Option:
A
Question Solution:
work done on the first three days is 37%. Hence, work done on the next 7 days is 63%. Since, this is A + B's work we get. One days work of (A + B) = 9%. Also, 5A = 4B. Hence A = 4% and B = 5% B, turns out to be the fastest worker.
Question:-
Option (A)
8 min
Option (B)
10 min
Option (C)
12 min
Option (D)
none of these
Correct Option:
B
Question Solution:
Let the work/minute of the four pipes be A, B, C and D respectively. Then, D - A = 1.66% and D + A = 5%
Question:-
Option (A)
8 min
Option (B)
10 min
Option (C)
12 min
Option (D)
none of these
Correct Option:
B
Question Solution:
Let the work/minute of the four pipes be A, B, C and D respectively. Then, D - A = 1.66% and D + A = 5%
Question:-
Option (A)
5
Option (B)
7.5
Option (C)
10
Option (D)
22.5
Correct Option:
C
Question Solution:
Ganesh takes 30 minutes to wash the car alone.
That means if Ganesh can wash 1/30 th part of car in 1 minute
Same way his father can wash 1/15th part of car in same 1 minute

That means in 1 minute together they finish 1/30 + 1/15 = 3/30 = 1/10 part of car wash
That means they together will take 10 minutes to wash the car