No let the radius of coin and marble be 1 and height of marble be 2 then volume of coins are 10pi r^2 h and volume of Marbles are 10 * 4 / 3 pi r^3
put the value and you will find that volume of the marbles is more then volume of the coins
Marbles will have more volume because twice the radipus of marble is equal to the height of th marble (approx) because it shape is like a sphere but in 5 rupee coin it is like a cylinder but its radious is about almost same as the marble but it has less height than its radious