help with C

Hard to see, but it looks like 1/4 of her spending was on petrol

   if 1/4 = 25   (90 degrees on the pie chart)

Then her total spending was 4 x L25 =  L100

She spent $25 on petrol....the central angle of the petrol  sector = 90°

So....this must represent  1/4  of the circle since the whole circle measures 360°

So.....she must have spent  4 times   $ 25   =  $100