At a certain fast food restaurant, Brian can buy 3 burgers, 7 shakes and 1 order of fries for exactly Rs 120. At the same place it would cost Rs 164.5 for 4 burgers, 10 shakes and 1 order of fries. How much would it cost for an ordinary meal of 1burgers, 1 shakes and 1 order of fries ? Choices
A) Rs. 31  B) Rs 41  C) Rs 21  D) Cannot be determined  E) None of these
Explanation :   Let the cost of 1 burger, 1 shake and 1 fries be x, y   and z.   Then   3x + 7y + z = 120 ... (i)   4x + 10y + z = 164.5 ... (ii)   x + 3y = 44.5 ... (iii) [ After subtracting (i) from (ii) ]   Multiplying (iii) by 4 and subtracting (ii) from it, we find   2y – z = 13.5 ...(iv)   Subtracting (iv) from (iii), we get x + y + z = 31.   Rs. 31nswer : Rs. 31
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At a certain fast food restaurant, Brian can buy 3 burgers, 7 shakes and 1 order of fries for exactly Rs 120. At the same place it would cost Rs 164.5 for 4 burgers, 10 shakes and 1 order of fries. How much would it cost for an ordinary meal of 1burgers, 1 shakes and 1 order of fries ?