75+ 15x ≥ 140
⇒ 15x ≥ 140-75
⇒ 15x ≥ 65
⇒ x ≥ 65/15
⇒ x ≥ 13/3
⇒ x ≥ 4 1/3
Final answer: x ≥ 4 1/3~
The sales tax rate would be 7%
23.54 - 22 = 1.54
1.54 / 22 = .07
.07 = 7%
first is 86
we know because of the sum of the interior angles of a triangle being 180, and that 5 + 6 =180
Speed = Distance / Time
Distance = Speed*Time
For this problem, we should bear in mind that current speed has an impact on the boat speed...
for upstream, the boat goes against the current, and so its speed is
U = V - C
where V is the speed of the boat
C is the current speed
for downstream, it will be:
D = V + C
Convert the problem into mathematical equations:
4D + 3U = 116
3D + 4U = 108
4(V+C) + 3(V-C) = 116
4V + 4C + 3V -3C =116
7V + C = 116
3(V+C) + 4(V-C) = 108
3V + 3C + 4V - 4C = 108
7V - C = 108
Solving the equations:
7V + C = 116
7V - C = 108
14V = 224
V = 16km/hr —-> speed of boat
to get C:
7(16) + C = 116
C = 4km/hr
