hard · GMAT Quant

A 100-kilogram blend is made from ingredients A, B, and C, containing 10%, 20%, and 40% protein, respectively. A costs 4 per kilogram and B costs 7 per kilogram. C normally costs 10 per kilogram, but if at least 30 kilograms of C are purchased, every kilogram of C costs 8 instead. The blend costs exactly $700, contains at least 10 kilograms of each ingredient, and each amount is a multiple of 5 kilograms. If the protein concentration is at least 22% but less than 28%, what is the sum of all possible amounts of ingredient A across all qualifying blends?

1. 4
2. 25
3. 45
4. 70
5. 120

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