How much time is required to cover the distance of 910 Km by a car driver, if he start with the initial speed of 40 Km/hr. and increases the speed by 5 Km/hr for every next hour ? Choose the correct choice from the following choices:  A) 11 hours  B) 12 hours  C) 13 hours  D) 14 hours  E) 15 hours
IT is AP series problem where   a= 40, d=5 , sum = 910   and n=?   910 = (n/2)*(2*40+(n-1)*5)   5n^2+75n-1820=0   n^2+15n-364=0   solving it, we get   n=13   so 13 hours   ANSWER:13 hours
<result>C</result>
How much time is required to cover the distance of 910 Km by a car driver, if he start with the initial speed of 40 Km/hr. and increases the speed by 5 Km/hr for every next hour ?