Solve.
Linda and Dave leave simultaneously from the same starting point biking in opposite directions. Linda bikes at 7 miles per hour and Dave bikes at 9 miles per hour. How long will it be until they are 24 miles apart from each other?
2/3 hrs
12 hrs
1 1/2 hrs
8/21 hrs
2007-06-06 08:41:16 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
1 1/2 hours
Dave travels 13.5 miles. Linda travels 10.5 miles.
x = number of hours
7x + 9x = 24
16x = 24
x = 24/16
x = 1 1/2
2007-06-06 08:45:56 · answer #1 · answered by DT 4 · 0⤊ 1⤋
7a + 9a = 24
16 a = 24 divide by 16
a = 24 / 16
a = 3 / 2 = 1 1/2 hrs
2007-06-06 15:46:48 · answer #2 · answered by muhamed a 4 · 0⤊ 1⤋
1 1/2 hrs
2007-06-06 15:53:35 · answer #3 · answered by jenlaceypink 1 · 0⤊ 1⤋
Let x represent the number of hours.
The distance Linda will bike in x amount of hours is 7x.
The distance Dave will bike in x amount of hours is 9x.
Because they are biking in opposite directions, the distance between them is 7x+9x in x amount of hours.
You want to find x when the distance between them is 24.
7x+9x=24
16x=24
24/16 = 3/2 hours or 1 1/2 hours.
2007-06-06 15:51:52 · answer #4 · answered by Linduh. 3 · 0⤊ 1⤋
Their combined speed is 16 mph
Distance = rate * time
24 = 16t
t = 24/16 = 3/2 = 1½ hrs.
.
2007-06-06 15:48:28 · answer #5 · answered by Robert L 7 · 0⤊ 1⤋