schweser practice exam vol 1 - 3-pm #81

This seems silly question, but for 2nd part, it’s asking whether the following is correct or not: in demand analysis of services in healthcare industry, for every 100 new hospital beds required, 20 additional doctors are needed. The answer said the above is wrong as its inference is supply. I don’t get it, 20 additional doctors needed sounds demand rather than supply to me. Anyone can explain? Thanks.h

the doctors provide healthcare services in the Healthcare Industry, so they belong to the Supply-side…

that was my thought too… what about the snow tires in the sentence above? is it 4 snow tires? or, tons of areas don’t get snow? … wasn’t really sure about it.