College

Four boys weighed themselves in different pairs and individually. The recorded weights of the pairs were 110 kg, 112 kg, 113 kg, 118 kg, 121 kg, and one weight was lost. The total weight of the four boys was 230 kg. What was the lost weight?

Answer :

Answer:

116

Step-by-step explanation:

you can use variables

a+b=110

a+c=112

a+d=113

b+c=118

b+d=121

add up the weights and you get 574 kg (you need to find c+d)

3a+3b+2c+2d=574

a+b+c+d = 230 as given then you multiply by 3 so you can cancel out 3a and 3b and subtract 690-574 because we multiplied by 3

you are left with c+d=116

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