Walking 7/6 of his usual rate, a boy reaches his school 5 min early. Find his usual time to reach the school?
Choose the correct option:
A) 22	B) 28	C) 99	D) 35	E) 66

Rationale: "speed ratio = 1 : 7 / 6 = 6 : 7 time ratio = 7 : 6 1 - - - - - - - - 7 5 - - - - - - - - - ? = 35 m answer : d"
Answer: D