Question 1008021
x = number of prawn
2x = number of salt
4x = number of plain
3x = number of cheese


x + 2x + 4x + 3x = 50


10x = 50


x = 5


number of prawn is 5.
number of salt is 10.
number of plain is 20.
number of cheese is 15.


add them up and you get 50.


problem statement says:


For every 2 salt and vinegar packets, there are 4 packets of plain crisps, 3 packets of cheese and onion crisps and 1 packet of prawn cocktail crisps.


for every 2 salt there are 4 plain.
4/2 = 2
there should be 2 times as many plain as salt.
there are because 20 is 2 times 10.


for every 2 salt there are 3 cheese.
3/2 = 1.5
there should be 1.5 times as many cheese as salt.
there are because 15 = 1.5 * 10.


for every 2 salt there is 1 prawn.
1/2 = .5
there should be .5 times as many prawn as salt.
there are because 5 is .5 * 10.


looks good.


you were asked how many salt and vinegar?
answer is 10.