Share 20 in the ratio 3 : 1.
Step 1 — Add the partsTotal parts = 3 + 1 = 4
Step 2 — Value of one partOne part = whole ÷ parts = 20 ÷ 4 = 5
Step 3 — Each share = parts × value3×5 = 15 and 1×5 = 5
Step 4 — Check it adds back15 + 5 = 20 ✓
and
The method never changes: add the parts, find one part, then scale each share up. Always check the two shares add back to the whole.