If a child walks at the rate of 5m/min from his home, he is 6 minutes late for school, if he walks at the rate of 7m/min he reaches half an hour earlier. How far is his school from his home ? Pick one:
A) 450 min
B) 540 min
C) 630 min
D) 360 min
E) none of these
Let the distance between home and school is x.   Let actual time to reach be t.   Thus, x/5 = t + 6 ---- (1)   and x/7 = t - 30 -----(2)   Solving equation 1 and 2   x = 630 min   ANSWER:630 min
<result>C</result>
If a child walks at the rate of 5m/min from his home, he is 6 minutes late for school, if he walks at the rate of 7m/min he reaches half an hour earlier. How far is his school from his home ?