Natasha rides her bike (at a constant speed) for 3 hours, helped by a wind of 3 miles per hour. Pedaling at the same rate, the trip back against the wind takes 9 hours. Find find the total round trip distance she traveled.
a. 12 miles
b. 27 miles
c. 27 / 2 miles
d. 54 miles
2007-12-10 14:04:19 · 3 answers · asked by . 1 in Science & Mathematics ➔ Mathematics
d = d
rt = rt
(b + 3)3 = (b - 3)9
b + 3 = 3b - 9
12 = 2b
6 = b
d = (6+3)3 = 27 mi.
2007-12-10 14:09:22 · answer #1 · answered by Philo 7 · 0⤊ 0⤋
9(bike -- 3) = 3(bike + 3) => bike = 6 mph
3(bike + wind)= distance = 3(6 + 3)miles = 27 miles
total distance = 2*27 miles = 54 miles
2007-12-10 14:18:25 · answer #2 · answered by sv 7 · 0⤊ 0⤋
let her constant speed = x mi/h
so the speed with help of wind = (x + 3) mi/h
the speed in return journey = (x - 3) mi/h
distance travelled while going = speed*time = (x+3)(3)= 3x + 9
distance travelled in return journey = (x-3)(9) = 9x - 27
since distance travelled is same
3x + 9 = 9x - 27
6x = 36
x = 6
so speed while going = 6+ 3 = 9 mi/h
speed while coming back = 6-3 = 3 mi/h
total distance traveled = 9(3) + 3(9) = 27 + 27 = 54 mi
2007-12-10 14:20:43 · answer #3 · answered by mohanrao d 7 · 0⤊ 0⤋