a brother 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?

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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=5000x=625brother will receive 5 × 625=3125 stamps 3x+x+x=31255x=3125x=625He will keep 3×625=1875 stamps