Apple Inc. posted a 26% jump in earnings Tuesday on the strength of sales of its iPhone, but Apple CEO Steve Jobs admitted that he doesn’t know how the economic downturn will effect Apple. The company posted fourth-quarter revenue of $7.9 billion compared to $6.2 billion in the year-earlier period. Net profits rose to $1.14 billion compared with $904 million in the same period in 2007. Quarterly iPhone units sold were 6.9 million compared with 1.2 million in the year-earlier period.
