Answer:
(8 - 12 )
Step-by-step explanation:
Given
x - 
y = 8
x + 
y = - 5
Multiply both equations through by 4 to clear the fractions
x - 2y = 32 → (1)
2x + 3y = - 20 → (2)
Multiplying (1) by - 2 and adding to (2) will eliminate the x- term
- 2x + 4y = - 64 → (3)
Add (2) and (3) term by term to eliminate x
0 + 7y = - 84
7y = - 84 ( divide both sides by 7 )
y = - 12
Substitute y = - 12 into either of the 2 equations and solve for x
Substituting into (1)
x - 2(- 12) = 32
x + 24 = 32 ( subtract 24 from both sides )
x = 8
solution is (8, - 12 )
Average speed for the entire trip, both ways, is
(Total distance) divided by (total time) .
We don't know the distance from his house to the gift store,
and we don't know how long it took him to get back.
We'll need to calculate these.
-- On the trip TO the store, it took him 50 minutes, at 6 mph.
-- 50 minutes is 5/6 of an hour.
-- Traveling at 6 mph for 5/6 of an hour, he covered 5 miles.
-- The gift store is 5 miles from his house.
-- The total trip both ways was 10 miles.
-- On the way BACK home from the store, he moved at 12 mph.
-- Going 5 miles at 12 mph, it takes (5/12 hour) = 25 minutes.
Now we have everything we need.
Distance:
Going: 5 miles
Returning: 5 miles
Total 10 miles
Time:
Going: 50 minutes
Returning: 25 minutes
Total: 75 minutes = 1.25 hours
Average speed for the whole trip =
(total distance) / (total time)
= (10 miles) / (1.25 hours)
= (10 / 1.25) miles/hours
= 8 miles per hour
Answer:
3
Step-by-step explanation:
Formula:
= 3
