Help Problem solving. Math

[whatanice]

Patulong Naman nga lods. Paano kaya to makukuha? With solution sana..thanks!!


Q. Security A rounds every 2mins and 20 sec in gate 1. Security B rounds every 1min 40 sec in gate 2. If they conduct rounds at the same time. After how many minutes they will round together again?
A. After 15mns B. After 16 C.17 D.18

 

[Ewankobatalaga]

A=140 sec
B=100 sec

just find the LCM then yun na yung answer
soo 700sec dapat, idk bat wala sa choices

 

[whatanice]

Sabi na eh. Sa choices Ang may mali .. btw salamat sa pag sagot!