HELP FAST PLEASE

Question

Tim and Cynthia leave Cynthia's house at the same time. Tim drives north and Cynthia drives west. Tim's average speed is 10 mph slower than Cynthia's. At the end of one hour, they are 70 miles apart. Find Cynthia's average speed

 

Answer 1

t = c -10

use the Pythagorean Theorem d^2 = sum of squares

cythia's distance = speed times time = c(1)= c

tim's distance = (c-10)(1)= c-10

70^2 = 4900 = c^2 + c^2 -20c +100

2c^2 -20c - 4800 = 0 Use the quadratic formula, complete the square, or graph the equation and find the positive x intercept

c = about 54.24 mph = Cynthia's speed

t = 10 mph less = about 44.24 mph = Tim's speed