Answer:
A) The width is 12 cm; the average time is 3 minutes
Step-by-step explanation:

Cross multiply.
5 × y = 3 × 20
5y = 60
5y ÷ 5 = 60 ÷ 5
y = 12
The width is 12 cm. Moving onto the time.

Cross multiply.
4 × y = 12 × 1
4y = 12
4y ÷ 4 = 12 ÷ 4
y = 3
The time is 3 minutes.
Since he must not exceed 8 hours driving in a day:
Let the distance of the picnic be = x km.
Therefore time for forward journey = x / 60
Return journey = x / 50
The total trip should not exceed 8 hours.
Therefore: x / 60 + x / 50 <= 8. LCM = 300
Taking LCM and multiplying on both sides:
5x + 6x <= 8(300)
11x <= 2400
x <= 2400/11
x <= 218.18
The picnic spot must be less than or equal to 218.18 km.
Answer:
(f-v)/a = t
Step-by-step explanation:
f = v + at
Subtract v from each side
f-v = v-v + at
f-v = at
Divide each side by a
(f-v)/a = at/a
(f-v)/a = t
Answer: A) 0
P(A and B) = 0 when events A and B are disjoint, aka mutually exclusive.
We say that two events are mutually exclusive if they cannot happen at the same time. An example would be flipping a coin to have it land on heads and tails at the same time.