hi few questions about the case

1)

Volume growth = Incidence patients - wheelchair patient deaths / wheelchair patient population base x changes in wheelchair lifetime / penetration

Volume growth = 55,275 - 26,000 / 875,000 = 3.3%

could you explain the formula and where 875000 is coming from

2) Growth = Volume growth + Price Growth

i think it should be growth= volume growth*price growth ?

3) it is said inthe case:" customer preferences in the US are similar to Europe and initial customer research indicates that there is demand for a more premium and technologically advanced product. Initial research indicates that this segment is about 25% of the total market"

"wheelchairs are paid for by the insurance company depending on the type of medical insurance that the patient has. Around 25% of insurance companies would cover up to the full cost of Comfort Chair's pricing"

i do not understand the information about the 25% given and then why 5% is used in the further market share calculation?

thanks a lot