This is from eg 21 from CFA Reading 40 (Equity valuation). The sol says that the IRR =9.98% if determined using a calcualtor. I tired this using TI BA II plus but found -24.78?

Are there alternating signs on the CFs? i.e. (-)(+)(-)

no, i used CF0 = -66.19 (stock price), and CF1 to CF7 as the dividends as given in the example