Ratio of Small to large marbles in the bag=1:3
It means ,number of small marbles in the bag will be multiple of 1 and number of Larger marbles in the bag will be multiple of 3.
So, number of small marbles be x and number of large marbles be 3x.
It is also given that, there are eight more large marbles than small marbles in the bag.
Expressing this statement in terms of equation
→3x=x+8
3x-x=8
2x=8
Dividing both sides by, 2 we get
x=4
Number of Small marbles =4 Marbles
Number of Large Marbles =4×3=12 Marbles