Bpp exam kits number 26 (c),

If something is uncertain, then if the actual figure is different from what has been estimated, then the final decision might be different.
Sensitivity measures what percentage change we can afford before reaching breakeven.
Here is a simple example:
If one year we have revenue of 20 and costs of 12, then there is a profit of 8. If the revenue is uncertain, then we still will get a profit provided that the revenue is more than 12, but we will make a loss of revenue is less that 12. So….we can afford the revenue to fall by 8 before we make a loss. In percentage terms this is a fall of 8/20*100 = 40%