Problema Solution
John has 50 marbles which are red, blue or yellow. Thirty-five of the marbles are either red or blue, and forty of the marbles are either blue or yellow. How many of each colour of marble does John have?
Answer provided by our tutors
let x red marble
y blue
z - yellow
then obtain a system of 3 equations
x + y + z = 40 35-40 + z +40- z + z = 50 z = 15
x + y = 35 x = 35-40 + z x = 10
y + z = 40 y = 40-zy = 25