Question 34337
let x be the chocolates worth $1.50 a pound 
and let y be the chocolates worth 90¢ a pound.

1.5x + 0.9y = 30(1.1) -- eq1
x + y = 30 --> x = 30 - y -- eq2
sub eq2 into eq1, u get

1.5(30-y) + 0.9y = 33
12 = 0.6y
y = 20

put back into eq2,
x + 20 = 30
x = 10