Let d = the length of the trail, miles
Note that
distance = speed * time
or
time = distance / speed.
The time, t₁, to travel the trail at 3 miles per hour is
t₁ = d/3 hours
The time, t₂, to travel back at 5 miles per hour is
t₂ = d/5 hours
Because the total time is 3 hours, therefore
t₁ + t₂ = 3
d/3 + d/5 = 3
d(1/3 + 1/5) = 3
d(8/15) = 3
Multiply each side by 15.
8d = 3*15 =45
d = 45/8 = 5 5/8 miles or 5.625 miles
Total distance = 2*d = 11.25 miles or 11 1/4 miles.
t₁ = 5.625/3 = 1.875 hours or 1 hour, 52.5 minutes
t₂ = 5.625/5 = 1.125 hours or 1 hour , 7.5 minutes
Answers ;
Time to travel at 3 miles per hour = 1.875 hours (1 hour, 52.5 minutes)
Time to return at 5 miles per hour = 1.125 hours (1 hour, 7.5 minutes)
Total distance traveled = 2*d = 11.25 miles.
Answer:
He burnt 1000 calories per hour when playing basketball.
Step-by-step explanation:
Let B be calories burned playing basketball, and C calories burned canoing.
1800 = B + 2C
3200 = 2B + 3C
From 1st equatipn, we get that B = 1800 - 2C
Replacing into the 2nd equation, we have:
3200 = 2(1800-2C) + 3C
3200 = 3600 - 4C + 3C
3200 = 3600 - 1C
C = 3600 - 3200
C = 400
Knowing C, we find B.
B = 1800 - 2C = 1800 - 2*400 = 1800 - 800 = 1000 calories.
the upper bound for the length is 
.
<u>Step-by-step explanation:</u>
Lower and Upper Bounds
- The lower bound is the smallest value that will round up to the approximate value.
- The upper bound is the smallest value that will round up to the next approximate value.
Ex:- a mass of 70 kg, rounded to the nearest 10 kg, The upper bound is 75 kg, because 75 kg is the smallest mass that would round up to 80kg.
Here , A length is measured as 21cm correct to 2 significant figures. We need to find what is the upper bound for the length . let's find out:
As discussed above , upper bound for any number will be the smallest value in decimals which will round up to next integer value . So , for 21 :
⇒
21.5 cm on rounding off will give 22 cm . So , the upper bound for the length is .
