Answer:44.01% of the spheres are copper
Explanation:
mass Cu + mass Pb = 4.35kg = 4.35 x 1000 = 4350g
But
Volume= mass / density
Let the volume of copper be C
density of Cu = 8.94 g/cm^3
Mass of copper = 8.94C
Let the volume of Lead be L
density of lead = 11.34g/cm^3
Mass of lead = 11.34L
Since
mass Cu + mass Pb = 4350kg
therefore
8.94C + 11.34L = 4350g----- EQN A
also
volume of copper + volume of lead = 423 cm^3
Volume of Lead ,L=423-C
putting the value of C = 423-L in Equation A becomes
8.94C + 11.34L = 4350g
8.94C + 11.34(423-C)= 4350g
8.94C+ 4796.82-11.34C=4350
4796.82-4350=11.34C- 8.94
446.82=2.4C
C= 186.175
Volume of copper = 186.175cm^3
Percentage copper = volume copper / total volume metal x 100/1
= 186.175 cm^3 / 423 cm^3 x 100/1
= 44.01%