The lost pair of weight can be found by subtracting the a known pair from
the total weight leaving the value of the lost pair.
<u>The lost weight of a pair of boys is 120 kg</u>
Reasons:
Let <em>a</em>, <em>b</em>, <em>c</em>, and <em>d</em><em> </em>represent the weights of the four boys, we have;
The number of ways of selecting pairs (two boys) of boys from a group of
four is given using combination formula as follows;
![_nC_r = \dfrac{n!}{r! \cdot (n - r)!}](https://tex.z-dn.net/?f=_nC_r%20%3D%20%5Cdfrac%7Bn%21%7D%7Br%21%20%5Ccdot%20%28n%20-%20r%29%21%7D)
Which gives;
![_4C_2 = \dfrac{4!}{2! \cdot (4 - 2)!} = 6](https://tex.z-dn.net/?f=_4C_2%20%3D%20%5Cdfrac%7B4%21%7D%7B2%21%20%5Ccdot%20%284%20-%202%29%21%7D%20%3D%206)
₄C₂ = 6
Therefore, the weights of the pairs are;
a + b = 110
a + c = 112
a + d = 113
b + c = 118
b + d = 121
c + d = Lost weight
a + b + c + d = 230 (given)
Therefore;
The lost weight, c + d = 230 - (a + b)
Which gives;
c + d = 230 - (110) = 120
The lost weight = c + d = 120
- <u>The lost weight = 120 kg</u>
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brainly.com/question/12974932