Acertain car is capable of accelerating at a rate of 10.60 m/s 2 . how long does it take for this car to go from a speed of 55 mi/h to a speed of 60 mi/h

Given:
acceleration rate: 10.60 m/s²
1st speed: 55 mi/hr
2nd speed: 60 mi/hr

notice that they use different units. m/s² and mi/hr. We need to convert one unit to the other for uniformity and consistency.

1 m/s = 2.23694 mi/hr     OR    1 mi/hr = 0.44704 m/s

1st speed: 55 mi/hr → 55mi/hr * 0.44704 m/s / 1mi/hr = 24.5872 m/s
2nd speed: 60 mi/hr → 60mi/hr * 0.44704 m/s / 1mi/hr = 26.8224 m/s

Acceleration formula:
Acceleration = Change in velocity / time → Vf-Vi / t

10.60 m/s² = (26.8224 m/s - 24.5872 m/s) / t
10.60 m/s²  * t = 2.2352 m/s
t = 2.2352 m/s ÷ 10.60 m/s²
t = 0.2109 s. 

It would take 0.2109 seconds to change from 55 mi/hr to 60 mi/hr at 10.60 m/s² acceleration rate.