13
Mark for Review
Packages in a warehouse are split into two groups.
Group
X contains 40 packages, and
group Y contains
110 packages
. If the mean mass of
the packages in
group X
is 24 kilograms (kg), and the
mean mass of the
packages
in group Y is 9 kg, what is the

mean mass,
in kg,
of all 150 packages?
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