Abrother and sister share out their collection of 5000 stamps in the ratio 5: 3. the brother then shares his stampswith two friends in the ratio 3: 1: 1, keeping most for himself. how many stampsdoes he keep for himself?

1) 5000 * (5 / (5+3) ) = 5000 * 5/8 = 3125

2) 3125 * (3 / (3+1+1) ) = 3125 * 3/5 = 1875

Let one part of the stamps be x.
5x+3x=5000;
8x=5000
x=625
brother will receive 5 × 625=3125 stamps
3x+x+x=3125
5x=3125
x=625
He will keep 3×625=1875 stamps