I think r should equal 32/7
Answer:
He drove the rest of the trip at 30 miles per hour
Step-by-step explanation:
The rule of the distance is D = v × t, where
∵ It is 170 miles from Bruce's house to the city where his brother lives
∴ D = 170 miles
∵ He drove for 2 hours at 55 miles per hour
∴ t1 = 2 hours and v1 = 55 miles/hour
→ By using the rule above find the distance of this part of his trip
∴ D1 = 55 × 2 = 110 miles
∵ The rest of the trip took 2 hours
∴ t2 = 2 hours
∵ D = D1 + D2
→ Substitute the values of D and D1 to find D2
∴ 170 = 110 + D2
→ Subtract 110 from both sides to find D2
∴ 60 = D2
∴ D2 = 170 - 110 = 60 miles
∵ The rest of the trip is 60 miles
∵ It took 2 hours
∵ D2 = v2 × t2
∴ 60 = v2 × 2
→ Divide both sides by 2
∴ 30 = v2
∴ v2 = 30 miles/hour
∴ He drove the rest of the trip at 30 miles per hour
Answer:
He bought 6 chairs and 10 tables.
Step-by-step explanation:
x+y = 16
he spent = $1800
1 chair = $50
y chairs = $50y
1 table = $150
x chairs = $150x
so, 150x+50y = 1800
we got two equations :
x+ y = 16
150x+50y = 1800
Using. substitution method,
x+y = 16
so, x = 16-y
Now
150x+50y =1800
or, 150(16-y) + 50y = 1800
or, 2400-150y+50y = 1800
or, 2400-1800 = 150y-50y
or, 600=100y
so, y = 6
now,
x+y = 16
or, x + 6 = 16
so, x = 10
Answer:
google
Step-by-step explanation:
Before the driver applies the brakes ( with the reaction time ):
d 1 = v0 · t = 20 m/s · 0.53 s = 10.6 m
After that:
v = v0 - a · t1
0 = 20 m/s - 7 · t1
7 · t1 = 20
t1 = 2.86 s
d 2 = v 0 · t1 - a · t1² / 2
d 2 = 20 m/s · 2.86 s - 7 m/s² · (2.86 s)²/2 = 57.2 m - 28.6 m = 28.6 m
d = d 1 + d 2 = 10.6 m + 28.6 m = 39.2 m
Answer: the stopping distance of a car is 39.2 m.
