Charlie owns one flute, two horns, and a harp for a total of 1+2+1=<<1+2+1=4>>4 instruments.
Twice as many flutes as Charlie is 2*1=<<2*1=2>>2 flutes,
Half as many horns as Charlie is 2/2=<<2/2=1>>1 horn
Thus, Carli owns 2+1=<<2+1=3>>3 instruments.
Therefore, the combined total number of musical instruments owned by Charlie and Carli is 4+3=<<4+3=7>>7 instruments.
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