So first let me assume that the Total profit of the racquets are 8 percentage and not individually.
Now to find the profit we can do
20 x 100= 2000
Now
8=x/2000*100
X= 160
And now for loss
10x80=800
Now
15= x/800*100
X=120
Now profit =
160-120 = 40
The profit was only 40
this can be solve by 3 variable equation
let x be the money of luke
y money of rachel
z money of daniel
first equation
x = y + 21
second equation
x = z + 48
third equation
x + y + z = 168
solving simultaneously
x =79
y = 58
z = 31
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