Need some help with this!

Jamie is hiking up a small mountain. he climbs up at a constant rate of 300 feet/hour until he reaches the peak at 1,500 feet. after that, he hikes down at the same rate to the base of the mountain. the equation that models jamie’s elevation, e, after t hours is e = . jamie’s elevation will be 600 feet after hours and after hours.

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

Mat bought a phone for $100. he has to pay $30 per mouth. if he has paid $640 in total, how many mouth has he had the phone?