Answer:
Her speed on the summit was 35 mph.
Step-by-step explanation:
Her speed on the summit was "x" mph while her speed while climbing was "x - 10" mph. The distance she rode uphill was 55 miles and on the summit it was 28 miles. The total time she explored the mountain was 3 hours. Therefore:
time uphill = distance uphill / speed uphill = 55 / (x - 10)
time summit = distance summit / speed summit = 28 / x
total time = time uphill + time summit
3 = [55 / (x - 10)] + 28 / x
3 = [55*x + 28*(x - 10)]/[x*(x - 10)]
3*x*(x - 10) = 55*x + 28*x - 280
3x² - 30*x = 83*x - 280
3x² - 113*x + 280 = 0
x1 = {-(-113) + sqrt[(-113)² - 4*(3)*(280)]}/(2*3) = 35 mph
x2 = {-(-113) - sqrt[(-113)² - 4*(3)*(280)]}/(2*3) = 2.67 mph
Since her speed on the uphill couldn't be negative the speed on the summit can only be 35 mph.
Write that as 7x. Writing it as x7 could lead to confusion. 7*x would be OK.
Answer:
2 rides & 4 games
Step-by-step explanation:
2 rides=$8
4 games=$8
8+8=$16
