Answer: About [tex]4.9\times10^7[/tex]
Explanation:
Given : The radius of each tire = 0.260 m
Circumference of tire = [tex]2\pi r[/tex] , where r is radius
[tex]= 2(\dfrac{22}{7})\times (0.260)\approx1.63\ m[/tex]
The distance traveled by the automobile= 80,000 km
= 80,000, 000 m [ ∵ 1 km= 1000 m]
Then , the number of revolutions made by each tire = (distance traveled) ÷ (Circumference of tire)
[tex]=\dfrac{80000000}{1.63}=49079754.6012\approx4.9\times10^{7}[/tex]
[Note : We are neglecting any backing up and any change in the radius due to wear.]
Hence, the number of revolutions [tex]\approx4.9\times10^{7}[/tex] .
