The government proposes a $3 billion plan for infrastructure, the marginal propensity to save (MPS)=0.25

1. If the plan is passed, it would raise aggregate demand by $_____ billion?

2. Instead, if $3 billion tax cuts, the aggregate demand would be ____less than? / equal to? / greater than?____ the government spending of $3 billion

Would appreciate steps and working out, thank you!!