In a row of buses, if bus Number 108 is 8th from the front and bus Number 201…
2016
In a row of buses, if bus Number 108 is 8th from the front and bus Number 201 is the 14th from the rear end. There are nine buses between them. How many buses are there in the row?
- A.
26
- B.
29
- C.
31
- D.
23
Attempted by 189 students.
Show answer & explanation
Correct answer: C
Solution: Let the total number of buses be N.
Position of bus 108 from the front = 8.
Position of bus 201 from the front = N − 14 + 1 = N − 13.
Given there are 9 buses between them, set up the equation: (N − 13) − 8 − 1 = 9.
Simplify and solve: N − 13 − 8 − 1 = 9 ⇒ N − 22 = 9 ⇒ N = 31.
Check: bus 201 is then 31 − 13 = 18th from the front. Buses between 8th and 18th = 18 − 8 − 1 = 9, which matches the condition.
Answer: 31 buses in the row.