I hope that the question is asking you what happens to planned consumption. Because the answer to that would be that planned consumption goes up by $160 billion.
The reason for that is that Yd is the disposable income and .8 is the marginal propensity to consume. That means that every time people get an extra $100, they will spend $80 of it (and save the other $20). So to figure out what happens when people get $200 billion extra, you just multiply $200 billion by .8 and that's where you get your answer -- if they get $200 billion more, they will spend $160 billion of it.