Answer:
300 balloons
Explanation:
Wei has $150.00 to make a garland using 60-cent balloons.
60 cents = $0.60
He wants to purchase 100 blue balloons = 0.60 × 100
He learns that the white balloons are on sale for half price, so the price of white balloons = 0.60/2
Let the number of white balloons be w.
Now the equation will be

60 + 0.30w = 150
0.30w = 150 - 60
0.30w = 90
w =

w = 300
Wei can buy 300 white balloons.