Given, diameter of a marble = 1.4 cm
∴Radius of marble=1.42=0.7 cm
So, volume of one marble =43π(0.7)343π×0.343=1.3723π cm3
Also given diameter of beaker = 7 cm
∴ Radius of beaker =72=3.5 cm
Height of water level raised = 5.6 cm
∴ Volume of the raised water in breaker
=π(3.5)2×5.6=68.6 π cm3
Now, required number of marbles =Volume of raised water in beakerVolume of one spherical marble
=68.6π1.372π×3=150