When dealing with statistics (probabilities of events etc) and histograms
1/4(8x+56)=20
1/4(8x)+1/4(56)=20
2x+14=20
2x=20-14
2x=6
X=3
21/6 simplified 7/2 or 3 1/2
13+5p+4r you add 7+6=13 then you bring down the rest
The original expression evaluates to 54.4 as shown in the first working.
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For some reason, 3.4 got transcribed to be 1.7 in the 3rd line of the second working. There is no math operation in the expression that requires 3.4 to be divided by 2.