An economy has the following marginal leakages:
Its government plans to increase national income (GDP) from 750bn750\text{bn}750bn to 890bn890\text{bn}890bn. By how much should government spending increase in order to achieve this objective?
105bn105\text{bn}105bn
35bn35\text{bn}35bn
140bn140\text{bn}140bn
560bn560\text{bn}560bn