Walking 7/6 of his usual rate, a boy reaches his school 4 min early. Find his usual time to reach the school?
Choose the correct choice from the following answers
A) 18 min  B) 19 min  C) 11 min  D) 28 min  E) 16 min
Speed Ratio = 1:7/6 = 6:7   Time Ratio = 7:6   1 -------- 7   4 --------- ? è 28 m   Answer: 28 min
<result>D</result>
Walking 7/6 of his usual rate, a boy reaches his school 4 min early. Find his usual time to reach the school?