Answer:
(0.70)x = 210
Explanation:
Let the total number of the balloons purchased = x
210 balloons were filled for a reception.
this number is 70% of the total number of balloons purchased.
so 70% of x will be equal to 210
Therefore, equation will be
70% of x = 210

(0.70)x = 210
Therefore, the equation can be used to find the total number of balloons is
(0.70)x = 210.