I think its easier to work out part (c) first:-
People who liked anything except burger = 3/8 + 1/4 + 1/5 = 33/40
So the fraction who liked burgers = 7/40.
7/40 of the total liked burgers so total people surveyed = (40/7) * 126 = 720
ANswer to c is 720.
a) Number who liked chicken and laksa = (3/8 + 1/4) * 720 = 450 Answer
b) Number who liked pasta = 1/5 * 720 = 144
Therefore 144-126 = 18 more people liked pasta than burger , Answer.
