Candidate is not required to give a quantitative solution, but he/she needs to understand and be able to explain in overall what's going on and what factors are causing the profit problem.
Candidate should lead the case whereas interviewer shares the data & information upon request.
A major juice producer sells packaged fruit juice to retail outlets. Normally, the juice is packed and sold in 16-ounce carton containers, but recently the producer added a new machine that packages the juice in 32-ounce plastic containers. So he was selling both the 16-ounce & the 32-ounce products. This allowed the business to grow 18% per year, but as sales continued to rise, profits kept falling.
The producer hired us to figure out why profits are falling despite higher revenues.