A hint to get started
Restrict a free parameter to feasible donor counts
A blood donation drive collected 520 litres from 1,200 donors, each with a unique type A, B or O. The volume collected per donor is:
| Blood type | Volume per donor (litres) |
|---|---|
| A | 0.35 |
| B | 0.40 |
| O | 0.45 |
By writing down a system of equations, find the range of possible numbers of type O donors.
[2017/MI/Promo/I/2]
CJC · Lecture · Example 8
Solve in terms of the type O count, then enforce both nonnegativity and integrality.