Rules for additive or multiplicative return calculations

Hi guys, just doing question 4 part Ai of the 2008 morning practice exam. They use an additive method for the return requirement for "Earn an average annual return of 8.7% plus management and administrative fees of 0.7%.

They used an additive approach rather than multiplying 1.087 * 1.007 which wiped my whole answer out. Is there any way to know which calculation the question is looking for?