The slope of a launch ramp cannot be too high or too low.
The length of a landing ramp must be long enough for riders to recover from the jump, but short enough so they do not lose speed for the next jump.
<h2>Step-by-step explanation:</h2>
BMX racetracks have jumps made for competition and racing. These ramps and jumps must be made in proper format. The height and slope of the jumps must be good enough to avoid any injury to the rider. A higher jump can cause a higher push to the bicycle and when it hit the ground, the rider may fall down and get hurt. In the same way the slope on both launch and land must be kept smooth and proper to avoid falling of the rider.
Because the first car wash does not cause the price to to down, but the ones after it do, you need onltake away 7 dollars of the price because it has only been discounted 7 times. Therefore 15-7=8 so 8 dollars is the answer.