Answer:
10
Step-by-step explanation:
Let Maria's entire budget be B.
"Maria spends her entire budget and consumes 5 units of x and 6 units of y."
5x + 6y = B
x = 2y
5(2y) + 6y = B
10y + 6y = B
16y = B
B = 16y
"Her income doubles and the price of y doubles, but the price of x stays the same."
Her new budget is now 2B, or 32y, and the price of y doubles to 2y, so 6 units of y now cost 12y. Now the price of y equals the price of x.
2B - 12y = 2(16y) - 12y = 32y - 12y = 20y
Since the price of x and y are now the same, and are both 2y. Since she has 20y left after buying 6 units of y, she can by 20y/2y = 10 units of x.
Answer: 10
