Answer:
270 to 150
Step-by-step explanation:
The summation symbol means we use the variable i in the equation from the given range. In this case, we are given with the equation 3 i - 15 and i ranges from 2 to 7. The summation using simply the calculator is equal to -9. The answer to this problem is -9.
75.89 + 0.12x = 27.41 + 0.36x
75.89 - 27.41 = 0.24x
48.48 = 0.24x
x = 48.48 / 0.24
x = 202
Each sent 202 text messages
So total, Rita gets 128 dollars, in 8 days