Question Number 105006 by mathocean1 last updated on 25/Jul/20

  Miranda did market in 3 day.  The monday, she bought 3kg of fish^�   ,2kg of meat ,1kg of rice at 10000 $.  The wednesday she bought 1kg of  fish, 3kg of meat, 2kg of rice at  10000$.  And the thursday she bought 4kg of  fish, 2kg of meat,3 kg of rice at  12500$.  1) Which price(sum) will spend Miranda  if she she go to the market at  saturday to buy at the same price  3kg of fish, 1kg of meat and 1.5kg of  rice?

Answered by Rasheed.Sindhi last updated on 25/Jul/20

 determinant ((,f,m,r,(sum)),((mon),3,2,1,(10000)),((wed),1,3,2,(10000)),((thu),4,2,3,(12500)),((sat),3,1,(1.5),?))  3x+2y+  z=10000    x+3y+2z=10000  4x+2y+3z=12500  By Cramer′s rule    x=( determinant (((10000),2,1),((10000),3,2),((12500),2,3))_ / determinant ((3,2,1),(1,3,2),(4,2,3))^ )    y=( determinant ((2,(10000),1),(3,(10000),2),(2,(12500),3))_ / determinant ((3,2,1),(1,3,2),(4,2,3))^ )    z=( determinant ((2,1,(10000)),(3,2,(10000)),(2,3,(12500)))_ / determinant ((3,2,1),(1,3,2),(4,2,3))^ )

Answered by Rasheed.Sindhi last updated on 25/Jul/20

3x+2y+  z=10000.........(i)    x+3y+2z=10000.........(ii)  4x+2y+3z=12500.........(iii)  (i)−(ii): 2x−y−z=0⇒z=2x−y     ^★ (i)⇒3x+2y+ (2x−y)=10000         ⇒5x+y=10000.........(iv)   ^★ (ii)⇒ x+3y+2(2x−y)=10000          ⇒ 5x+y=10000   ^★ (iii)⇒4x+2y+3(2x−y)=12500           ⇒10x−y=12500........(v)  (iv)+(v):15x=22500⇒x=1500$  5x+y=10000⇒y=10000−5(1500)         y=2500$  (i)⇒  z=10000−3x−2y  (i)⇒   z=10000−3(1500)−2(2500)  z=500$  Conclusion:All things are very  expensive in  mathocean1′s   country.

Commented bymathocean1 last updated on 25/Jul/20

hahahaha not too expensive ...  It is the problem of  currency($ instead of XAF) .  Thank you sir.

Commented byRasheed.Sindhi last updated on 26/Jul/20

hahahaha......Amusing  information I received(through  internet!) I was totally unaware  of the currency  of your country(XAF)....  Anyway you have increased  your expences by using $ sign :)

Commented bymathocean1 last updated on 25/Jul/20

Exactly sir!