Lucy stands on a set of faulty scales that state her mass as 48 kg. David's mass from the same scales is recorded as 56 kg and their combined mass is recorded as 107 kg.
Assuming the magnitude and nature of the errors was constant, what is the true mass of David?
let Lucys true weight be L and Davids be D
Also, let the error of the scale be e
then we have
(1) L+e=48
(2) D+e=56
(3) D+L+e=107
from (1)+(2)-(3) we get
L+e+D+e-D-L-e=48+56-107
e=-3
thus we get
L=48-e=51
D=56-e=59
Thus Davids mass is 59kg
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Posted by Daniel
on 2019-06-24 11:56:26 |
solution