Walking 7/6 of his usual rate, a boy reaches his school 3 min early. Find his usual time to reach the school?
Choose the correct choice from the following answers:
A) 21  B) 28  C) 99  D) 77  E) 66
Speed Ratio = 1:7/6 = 6:7   Time Ratio = 7:6   1 -------- 7   3 --------- ?   = 21 m   21nswer:21
<result>A</result>
Walking 7/6 of his usual rate, a boy reaches his school 3 min early. Find his usual time to reach the school?