Question

27 pencils and 31 rubbers together cost rupees 85 while 31 pencils and 27 rubbers together cost rupees 89. find the cost of 2 pencils and 1 rubber

Answer 1

Let cost of one pencil be x and that of one rubber be y,
Then, according to question,

(27x+31y = 85)*27            ....(i)
(31x+27y = 89)*31            ....(ii)

729x+837y = 2295
961x+837y = 2759

Subtracting (i) from (ii) we get,

961x+837y = 2759
729x+837y = 2295
(-)    (-)          (-)

232x           =464
      x           =464/232
      x           =2

Plugging x=2 in (i), we get

27x+31y = 85
27*2+31y = 85
54+31y = 85
31y = 85-54
y = 31/31
y = 1

Therefore, x=2 and y=1

:)