A suspicious-looking manruns as fast as he can along a moving sidewalk from one

Question

A suspicious-looking manruns as fast as he can along a moving sidewalk from one end to theother, taking 3.50 s. Then security agentsappear and the man runs as fast as he can back along the sidewalkto his starting point, taking 11.0 s. Whatis the ratio of the man's running speed to the sidewalk's speed?(running speed / sidewalk speed)
1
A suspicious-looking manruns as fast as he can along a moving sidewalk from one end to theother, taking 3.50 s. Then security agentsappear and the man runs as fast as he can back along the sidewalkto his starting point, taking 11.0 s. Whatis the ratio of the man's running speed to the sidewalk's speed?(running speed / sidewalk speed)
1
A suspicious-looking manruns as fast as he can along a moving sidewalk from one end to theother, taking 3.50 s. Then security agentsappear and the man runs as fast as he can back along the sidewalkto his starting point, taking 11.0 s. Whatis the ratio of the man's running speed to the sidewalk's speed?(running speed / sidewalk speed)
1
A suspicious-looking manruns as fast as he can along a moving sidewalk from one end to theother, taking 3.50 s. Then security agentsappear and the man runs as fast as he can back along the sidewalkto his starting point, taking 11.0 s. Whatis the ratio of the man's running speed to the sidewalk's speed?(running speed / sidewalk speed)
1
A suspicious-looking manruns as fast as he can along a moving sidewalk from one end to theother, taking 3.50 s. Then security agentsappear and the man runs as fast as he can back along the sidewalkto his starting point, taking 11.0 s. Whatis the ratio of the man's running speed to the sidewalk's speed?(running speed / sidewalk speed)
1
A suspicious-looking manruns as fast as he can along a moving sidewalk from one end to theother, taking 3.50 s. Then security agentsappear and the man runs as fast as he can back along the sidewalkto his starting point, taking 11.0 s. Whatis the ratio of the man's running speed to the sidewalk's speed?(running speed / sidewalk speed)
1
A suspicious-looking manruns as fast as he can along a moving sidewalk from one end to theother, taking 3.50 s. Then security agentsappear and the man runs as fast as he can back along the sidewalkto his starting point, taking 11.0 s. Whatis the ratio of the man's running speed to the sidewalk's speed?(running speed / sidewalk speed)
1

Explanation / Answer

   Let the man's speedbe    vm   and thatof sidewalk be    vw.    For the first part, effective speed ofman   v1   =   vm   +   vs    For the second part effective speed ofman   v2   =   vm   -   vs    also   speed   =   distance(d) / time(t)    =>   v1   =   d/ 3.50          vm   +   vs   =   d/ 3.50   -------- (1)       and   v2   =   d/ 11.0       vm   -   vs   =   d/11.0         --------(2)    adding   (1) and (2)       2 *vm   =   d/3.5   +   d/ 11.0                   =   14.5* d / 38.5                vm   =   14.5* d /77         ---------(3)    subtracting (2) from (1)    2 *vs   =   d/3.5   -   d/ 11.0                =   7.5* d / 38.5       vs   =   7.5* d /77               -----------(4)    Dividing equation (3) by equation (4)    vm /vs   =   (14.5 * d /77) /(7.5 * d / 77)                =   29/15    also   speed   =   distance(d) / time(t)    =>   v1   =   d/ 3.50          vm   +   vs   =   d/ 3.50   -------- (1)       and   v2   =   d/ 11.0       vm   -   vs   =   d/11.0         --------(2)    adding   (1) and (2)       2 *vm   =   d/3.5   +   d/ 11.0                   =   14.5* d / 38.5                vm   =   14.5* d /77         ---------(3)    subtracting (2) from (1)    2 *vs   =   d/3.5   -   d/ 11.0                =   7.5* d / 38.5       vs   =   7.5* d /77               -----------(4)    Dividing equation (3) by equation (4)    vm /vs   =   (14.5 * d /77) /(7.5 * d / 77)                =   29/15

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.