The Multiplier..?

This question is poorly worded, and there is not enough information to determine the multiplier. In order to figure out what the multiplier is, if any, you need the initial change in spending then the Marginal Propensity to Consume, or the Marginal Propensity to Save (to which you'll work to figure out the MPC) OR you can get it from the initial change and the subsequent change in rGDP.