Qus1 Rekha and Meeta can weave a sweater in 12 daysMeet
Qus1. Rekha and Meeta can weave a sweater in 12 days ,Meeta and Payal in 15 days, Payal and Rekha in 20 days. In how many days will they weave it, if they weave together ? In how many days will each of them weave, if they weave it alone?
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Right Answer is:
SOLUTION
let
regha =a
meetha =b
payal = c
meera = d
Rekha and Meeta can weave a sweater in 12 days
ie a &b = 12 days
a+b = 12 --------------------------equation (1)
Meeta and Payal in 15 days
ie b&c = 15
b+c = 15------------------------------------(2)
Payal and Rekha in 20 days.
ie a &c = 20 days
a+c = 20 -----------------------------------(3)
combining (1) and (2)
(2)-(1)
a+b = 12
b+c = 15
-----------------
3= c-a ------(4)
now combining (2) and (3) [(3)-(2)]
b+c = 15
a+c = 20
----------------
5= a-b ---------------(5)
comparing the (5) and (1)
(5)+(1)
5= a-b
12=a+b
--------------
17= 2a
a=17/2
apply this in (1)
a+b =12
17/2+b =10
b= 10-7/2
= 13/2 days
now apply this in (2)
b+c = 15
13/2+c =15
c= 15-13/2
= 17/2
if the work all together
= a+b+c = 17/2+13/2+17/2 = 47/2 days
if
they weave it alone
days taken by a =17/2 days
days taken by b= 13/2 days
days taken byc = 17/2 days