Can someone plz help me on this

Two blends of tea are mixed to make a blend that will be sold at the fair. black tea sells for $2.20 per pound and orange pekoe tea sells for $3.00 per pound. how much of each should be used to obtain a 4lb blend selling for $2.50 per pound?

Can someone me with this problem i don't understand i need

Lines a and b are parallel. what is the value of x? -5 -10 -35 -55