single room double room

**blover** · 10-07-2008, 02:15 PM

please suggest shortest efficient technique

like the technique shown below the point 47

for solving ratio question.

**e.cartman** · 10-07-2008, 02:39 PM

I donno short-cut but this is my method. I get B.
15 min is 1/4 hr
20 min 1/3 hr
1400 rooms * 1/4 = 350 hrs by 1 person
420 * 1/3 = 140 hrs by 1 person
Total 490 hrs by 1 person
Or 490/7 = 70 men for 7 hrs.

**blover** · 10-07-2008, 02:49 PM

20 minutes is 1/3 of hr or 2/3 ?

**e.cartman** · 10-07-2008, 02:51 PM

Oops! My mistake. I corrected it in situ. To think the authors have an answer option to catch that.

**coolaman** · 10-07-2008, 02:56 PM

I got B. 70 persons.

**blover** · 10-07-2008, 03:06 PM

how suggest technique?

**bose** · 10-10-2008, 11:17 AM

1 room by 1 person in 15mins
nin 7 hrs i.e. 420 mins one person can do 28 rooms
so to do 1400 rooms we need 1400/28=50 people
similary we get 20 people for 420 large rooms
ands 70

**genius_in_the_gene** · 10-10-2008, 08:31 PM

Imo B.

**trigeminal** · 10-11-2008, 02:42 PM

B
Total time required- (1400x15)+(420x20)=29400min
Total time available- 7x60 = 420min
No of persons required=29400/420 = 70 persons
(easy to calculate after omitting zeroes)