A man driving at 4/5th of his original speed reaches his destination 15 mins later than the usual time . The usual time ( in minutes ) is :
Answer & explanation
Correct answer: option 4
Ratio old : new
Speed 5 : 4
Time 4 : 5
According to question , 1R = 15 min
4R = 15 × 4 = 60 min
So , usual time is = 60 min