WILL GIVE BRAINLEIST DUE AT 9:45 P.M. PLS HURRY SUPER EASY.
The table shows the amount it cost to rock climb at an indoor rock climbling facility, based on the number of hours. What is the rule to find the amount charged to the rock climb for x hours?

Time: 1 2 3 4 x
Amount:13 21 29 37 ?