A circular jogging track forms the edge of a circular lake that has a diameter of 2 miles.
A circular jogging track forms the edge of a circular lake that has a diameter of 2 miles. Johanna walked once around the track at the average speed of 6 miles per hour. If t represents the number of hours it took Johanna to walk completely around the lake, which of the following is a correct statement?
Answer/Solution
0.5< t < 1.5
Steps/Work
D=2, and R=1
circumference thus is 2pi miles
we know that she walked 6mph
knowing the formula rt=D, we can deduce that t= D/r
D is 2pi miles and r is 6mph
t = 2pi/6
pi can be rewritten as 22/7
2*22/7 = 44/7 and multiply this by 1/6 = 44/42. This is greater than 0.5, but less than 1.5, therefore, 0.5<t<1.5. Answer choice A.
circumference thus is 2pi miles
we know that she walked 6mph
knowing the formula rt=D, we can deduce that t= D/r
D is 2pi miles and r is 6mph
t = 2pi/6
pi can be rewritten as 22/7
2*22/7 = 44/7 and multiply this by 1/6 = 44/42. This is greater than 0.5, but less than 1.5, therefore, 0.5<t<1.5. Answer choice A.