Josh needs a 15 yard head start on Amy to make a fair race. How long will it take Amy to catch up to Josh if Josh travels at 7 yards per second and Amy travels at 10 yards per second.
2006-11-02 07:42:29 · 5 answers · asked by ♥♥♥m.d.p♥♥♥ 2 in Education & Reference ➔ Homework Help
15 + 7x = 10x
It will take her 5 seconds
15 + 7(5)= 10(5)
50 = 50
2006-11-02 07:46:26 · answer #1 · answered by unknown persons 2 · 0⤊ 0⤋
Let x = the time in seconds until the Amy catches up with Josh
so in time x, Josh will have travelled 7x + 15 yards
and Amy will have travelled 10x
We know that at time x, they will have travelled the same distance, so:
7x + 15 = 10x
3x = 15
x = 5 seconds
in 5 seconds, Josh will have travelled (7*5) + 15 = 50 yards and Amy will have travelled (10*5) = 50 yards.
2006-11-02 15:47:15 · answer #2 · answered by disposable_hero_too 6 · 1⤊ 0⤋
This is all based on the formula: Distance = Rate x Time.
You are trying to find time, but only have one known--Rate. So we need to solve for D, then substitute D to get Time.
So, let D = distance Amy runs. Therefore D-15 = distance Josh Runs. They both run for the same amount of time, so we need to rewrite the D=RT formula to express it in time: T = D/R
Amy's rate is 10 y/s. Josh's Rate is 7 y/s.
D/10 = (D-15)/7
Multiply both sides by 70 to clear fractions.
7D = 10(D-15)
7D = 10D -150
combine
3D = 150
D = 50 yards (the distance Amy runs).
Substituting in for Amy's equation:
T = D/R
T = 50/10 y/s
T = 5 seconds.
And just for giggles, look at Josh.
D-15 = R x T
50 - 15 = 7 x 5
35 yards= 35 yards
2006-11-02 15:55:56 · answer #3 · answered by Grover 3 · 0⤊ 0⤋
You should make a graph. the slope for one line is 10. The other other lines slope is 7 and the y interception is 15. See where they intercept.
2006-11-02 15:48:24 · answer #4 · answered by ice_purple969 4 · 0⤊ 1⤋
Uphill or Down hill?
2006-11-02 15:50:29 · answer #5 · answered by Dane N 1 · 0⤊ 1⤋