1B
the flat is £80000, 5% of that is £4000, so she still have to pay £76000.
1C
from January to December she saved £3000, she still has £73000 more to go to pay the flat.
1D
we know she's saving on average £250 per month, and we also know she still has £73000 more to go, so 73000/250 = 292 more months for the rest of the payment of the flat.
