A set of weighing scales measures weight in kilograms. A boy, a girl, and a dog stand on the scales in three different ways.
How heavy would the boy, girl, and dog weigh together?
Let the weight of the boy, girl, and dog be b, g and d respectively.
b + g = 118, g + d = 72, b + d = 78
Adding all three equations: 2b + 2g + 2d = 268.
Hence the weight of all three, b + g + d = 134 kg.
How heavy would each be individually?