F1數學(15點)

389 x (0.83+0.14+y) = 389, so 0.83+0.14+y = (389/389) =1.

therefore y = 1 - (0.83 + 0.14) = 1 - 0.97 = 0.03 = 0.03 x100% = 3%.


The First class seats = 389 x 0.03 = 12 seats (round up to nearest integer).


Let Z be econ class seats.

As the business class seats increased to 19%, then 1 - (0.19 +0.03 + Z), hence the econ class seats of Z decreases to 0.78 x 100 =78% (assuming first class seats no change)


The econ class seats = 389 x 0.78 = 303 seats (round up to nearest integer).


Hope this simple maths answer will help you!

a) 389 * (1 - 83% - 14%)
= 12 (correct to the nearest integer)
.'. there are 12 first class seats.

b) 389 * (1 - 19% - 3%)
= 304 (correct to the nearest integer)
.'. there are 304 economy seats are now on the aeroplane.

(A) First class seats = seats that aren't economy or business
Therefore = (100-83-14)% = 3%
Total of 389 seats, therefore there are:
3% * 389 = 11.67 = 12 first class seats (correct to nearest integer)

(B) Because business class = 19%; first class = 3%
Therefore: (100-19-3)% = 78%
there are 78% * 389 = 303.42 = 303 economy class seats (correct to nearest integer)