The juice stall at the circus stocked just 2 brands of orange juice tetra packs. Brand A costs $1 per pack and brand B costs $1.5 per pack. Last week , brand A contributed to a% of stall’s revenue and accounted for b% of sales of juice tetra packs. Which of the following expresses a in terms of b?
Pick one:  A) 100b/(150 – b)  B) 200b/(250-b)  C) 200b/(300-b)  D) 250b/(400-b)  E) 300b/(500-b)
1. Let the number of units sold be 100. Then n units of A are sold and (100-n) units of B are sold.   Total revenue= Revenue due to A + Revenue due to B   = (No.of units of A sold * Cost/unit of A) + (No.of units of B sold * cost/unit of B)   = b *1 + (100-b) *1.5   = b + (150-1.5b) --- (1)   2. But we know, revenue due to A = a%. of the total revenue --- (2)   3. To express a in terms of b we need to relate (1) and (2)   4. a% = b / ( b + (150-1.5b))   or a= 100b / 150-0.5b = 200b/(300-b)   200b/(300-b)
<result>C</result>
The juice stall at the circus stocked just 2 brands of orange juice tetra packs. Brand A costs $1 per pack and brand B costs $1.5 per pack. Last week , brand A contributed to a% of stall’s revenue and accounted for b% of sales of juice tetra packs. Which of the following expresses a in terms of b?