Answer:
x = gym memberships, and y = bottles of water
30x + 7y = 1050.....when x = 28
30(28) + 7y = 1050
840 + 7y = 1050
7y = 1050 - 840
7y = 210
y = 210/7
y = 30....so he would have to sell 30 water bottles
Step-by-step explanation:
Answer:
Step-by-step explanation:
This is good! The length of the metal is 20 inches longer than the width. But we fold up 4-inch flaps on each side, so the height of the box is 4 inches, and the length and width will each decrease by 8 inches (4 inches on each side). Since the length and width decrease by the same amount, the length will still be 20 inches longer than the width. So the equations would be:
l = w + 20
vol = l x w x h = 1716 in3
1716 = (w + 20)(w)(4)
1716 = 4w2 + 80w
4w2 + 80w - 1716 = 0
4(w2 + 20w - 429) = 0
4(w + 33)(w - 13) = 0
w + 33 = 0, so w = -33
w - 13 = 0, so w = 13
Since the width can't be negative, the width of the box is 13 and the length is 33 (13 + 20).
But remember, the length and width of the piece of metal are each 8 inches longer than the box, so it was 41 inches by 21 inches.
The height at t seconds after launch is
s(t) = - 16t² + V₀t
where V₀ = initial launch velocity.
Part a:
When s = 192 ft, and V₀ = 112 ft/s, then
-16t² + 112t = 192
16t² - 112t + 192 = 0
t² - 7t + 12 = 0
(t - 3)(t - 4) = 0
t = 3 s, or t = 4 s
The projectile reaches a height of 192 ft at 3 s on the way up, and at 4 s on the way down.
Part b:
When the projectile reaches the ground, s = 0.
Therefore
-16t² + 112t = 0
-16t(t - 7) = 0
t = 0 or t = 7 s
When t=0, the projectile is launched.
When t = 7 s, the projectile returns to the ground.
Answer: 7 s