Dividing in a Ratio
To split a total in a given ratio, add the ratio parts to get the number of equal shares, then hand out that many. If $8,000 is divided in the ratio 3 : 5, there are 3 + 5 = 8 shares, each worth 8000/8 = $1,000, so the two amounts are $3,000 and $5,000. The single most useful number here is the "value of one part": once you know it, every share is a quick multiply. The GRE often gives you a difference instead of a total — "the shares differ by $2,000" — and the same idea handles it: the difference is 5 − 3 = 2 parts, so one part is $1,000. Watch the order of the answer choices and answer exactly what is asked (the larger share, the difference, or the total). For three-way splits, the method is identical: divide the total by the sum of all parts.
✅ Solved examples
✏️ Practice — try these, take hints as needed
📝 Topic test — 8 questions
Auto-graded with full solutions; saved to your dashboard. Use the calculator and formula sheet (top-right) any time.
Formula Reference Sheet
Ratio basics
| Ratio as a fraction | a : b = a/b (same information) |
|---|---|
| Scaling a ratio | a : b = ka : kb for any k ≠ 0 |
| Dividing a total in a : b | shares = [a/(a+b)] × T and [b/(a+b)] × T |
| Combining a : b and b : c | make the shared term equal, then read a : b : c |
Proportion & variation
| Proportion (cross-multiply) | a/b = c/d ⇔ a·d = b·c |
|---|---|
| Direct variation | y = kx ⇒ y₁/x₁ = y₂/x₂ (ratio constant) |
| Inverse variation | y = k/x ⇒ x₁y₁ = x₂y₂ (product constant) |
| Mean proportional of a and b | √(ab) |