Answer:
P = 7.7 C + 1.1 XC
Step-by-step explanation:
From the question, it is noted that the price of helium required to fill each of the balloons would increase by 10%. Let the current price of helium be C, so that;
10% of C = 0.1 C
The price of helium next year = C + 0.1 C
            = 1.1 C
Cost of 7 small balloons = 1.1 C * 7
             = 7.7 C
Cost of X large balloons = 1.1 C * X
             = 1.1 XC
The total price, P for helium next year = 7.7 C + 1.1 XC
Thus, the equation to find the total price of helium that would fill the balloons next year is;
P = 7.7 C + 1.1 XC
