I don't think it's proportional, because in order for a question to be a proportional question has/could be to be like this:
Gasoline costs $2.79 per 2 gallon. How much will it cost for 8 gallon. Then, we cross multiply and all to find the answer.
Answer:
a ) If r ⇒ p
If q ⇒ p
r ∪ q
If r∪p ⇒ ¬ r
∴ s
b) The argument is invalid
Step-by-step explanation:
The argument is invalid because we do not with precision if b), because we do not have enough information about it, and this is because the previous sentences does not mention information about the donkey. We cannot infer something when we do not have enough information.
The minimum distance will be along a perpendicular line to the river that passes through the point (7,5)
4x+3y=12
3y=-4x+12
y=-4x/3+12/3
So a line perpendicular to the bank will be:
y=3x/4+b, and we need it to pass through (7,5) so
5=3(7)/4+b
5=21/4+b
20/4-21/4=b
-1/4=b so the perpendicular line is:
y=3x/4-1/4
So now we want to know the point where this perpendicular line meets with the river bank. When it does y=y so we can say:
(3x-1)/4=(-4x+12)/3 cross multiply
3(3x-1)=4(-4x+12)
9x-3=-16x+48
25x=51
x=51/25
x=2.04
y=(3x-1)/4
y=(3*2.04-1)/4
y=1.28
So now that we know the point on the river that is closest to Avery we can calculate his distance from that point...
d^2=(x2-x1)^2+(y2-y1)^2
d^2=(7-2.04)^2+(5-1.28)^2
d^2=38.44
d=√38.44
d=6.2 units
Since he can run at 10 uph...
t=d/v
t=6.2/10
t=0.62 hours (37 min 12 sec)
So it will take him 0.62 hours or 37 minutes and 12 seconds for him to reach the river.