The answer = 3480
504 + 10% is not 840 so it must be a calculation error.
The answer is 4550
5.5% of 4800= 5.5% * 4800= 0.055 * 4800= 264
4800
That is 4800
840
90% of 4800 = 4320= 90% * 4800= 90%/100% * 4800=43200/10= 4320
The value of 4800 is 4800 and probability has nothing to do with it.
400 x 12 = 4,800
30% of 4800 = 144030% of 4800= 30% * 4800= 0.30 * 4800= 1440
840