C I’m pretty sure hope this helps
Given:
One time payment, <em>p </em>= $300
Payment per month, <em>q = </em>$65
Number of months paid, <em>n</em> = 5
The objectiv is to find the amount she paid in 5 months.
Let <em>x </em>be the amount she paid in 5 months. Then the the formula is,

Let's substitute the values.

Hence, total amount paid in 5 months is $625.
It's 12x. you just combine both numbers
The t-value measures the size of the difference relative to the variation in your sample data. Put another way, T is simply the calculated difference represented in units of standard error. The greater the magnitude of T, the greater the evidence against the null hypothesis.