There are at most 15 people composed of children and adults who ride in an elevator that has a capacity of 600 kilograms. If children’s weight averages 30 kilograms and adult’s weight averages 55 kilograms, how many children and adults are in the elevator?
And solution

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Answers

  • Brainly User
2016-03-08T00:57:48+08:00
X + y ≤ 15   ("at most" means maximum.  Use inequality symbol.)

Representation:
     Number of Children: x                  
     Children's weights: 30x

     Number of Adults: 15-x
     Adults' weights: 55(15-x)  or -55x + 825

Equation:
     (30x) + (-55x + 825) = 600

     30 x - 55x + 825 = 600

     -25x + 825 = 600

     -25x = 600 - 825

     -25x = -225
 
     -25x/-25 = -225/-25
  
      x = 9

Number of children: x      ⇒ 9 children
Number of adults: 15-x    ⇒ 15-9 = 6 adults

ANSWER:  9 children and 6 adults

Check:
x + y ≤ 15
9 + 6 ≤ 15
15 ≤ 15  (True.  The total number of children and adults is
                at most or maximum 15.)
--------------------
Weights:
  30 kg (9) + 55 kg (6) = 600 kg
   270 kg + 330 kg = 600 kg
   600 kg = 600 kg   (True)





 
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