Florence and Jackie are running laps on a circular quarter-mile track. If Florence completes each lap in 75 seconds and Jackie completes each lap in 90 seconds, how many laps will Jackie have run before she’s passed by Florence, assuming they start at the same time.
1) 5
2) 6
3) 7
4) 8
5) 9

• This problem can be tricky with algebra, but conceptually it’s much easier. Each time Jackie completes a lap, Florence spends an extra 15 seconds on another lap. ans is 5 : Therefore, Florence runs an extra of a lap each time Jackie runs one.
  
  So after 5 of Jackie’s laps, Florence will be completing a sixth. Accordingly, Jackie will have run exactly five laps when she’s passed by Florence.
• 12 years agoHelpfull: Yes(20) No(2)
• lcm of 75 and 90 is 450 and 450/90(time taken by jackie)=5
• 12 years agoHelpfull: Yes(16) No(1)
• Ans is 5;
  when jackie completes 1 lap ,florence complete 15 sec of her next lap .
  therefore to pass jackie by florence once again , laps covered by jackie should be (75/15=5)
  i.e 5 laps after starting at same time..
  
  
• 12 years agoHelpfull: Yes(6) No(1)
• 90-15=15
  75/15=5 Ans...
• 12 years agoHelpfull: Yes(5) No(1)
• take out lcm of 75 & 90 then find out the no. of laps they coverd within that time
• 12 years agoHelpfull: Yes(4) No(1)
• 6 should be the ansr......
• 12 years agoHelpfull: Yes(2) No(7)