!!!!!!!!!! 50 POINTS !!!!!!!!!!!! How would you go about solving this? Please provide formulae / explanation if needed, thank you.

Answer:
W = 1.9
Step-by-step explanation:
The mean is a measure of central tendency calculated by dividing the sum of a set of values by the total number of values.
[tex]\boxed{\rm Mean=\dfrac{\text{Sum of a set of values}}{\text{Total number of values}}}[/tex]
If Larry has a total of 7 parcels to deliver and the mean weight of the parcels is 2.7 kg, then the total weight of all the parcels is:
[tex]\rm Total\;weight=2.7 \; kg/parcel \times 7\;parcels\\\\ Total\;weight= \boxed{18.9\; \rm kg}[/tex]
If Larry delivers 3 of the parcels, and each of these parcels has a weight of W kg, then the total weight of the delivered parcels is:
[tex]\rm \text{Total weight of delivered parcels}=W\; kg/parcel \times 3\;parcels\\\\\text{Total weight of delivered parcels}=\boxed{3W\; \rm kg}[/tex]
If the mean weight of the other 4 parcels if 3.3 kg, then the total weight of the other 4 parcels is:
[tex]\rm \text{Total weight of other 4 parcels}=3.3\; kg/parcel \times 4\;parcels\\\\\text{Total weight of other 4 parcels}=\boxed{13.2\; \rm kg}[/tex]
To determine the value of W, set the sum of the delivered parcels and the other 4 parcels equal to the total weight of the parcels:
[tex]3W+13.2=18.9[/tex]
Solve for W:
[tex]3W+13.2-13.2=18.9-13.2\\\\\\3W=5.7\\\\\\\dfrac{3W}{3}=\dfrac{5.7}{3}\\\\\\W=1.9[/tex]
Therefore, the value of W is:
[tex]\Large\boxed{\boxed{W=1.9}}[/tex]