Question

Four traffic signals turn red together. If signals turn red at intervals of 2,5,8 and 10 seconds respectively after what interval of time will they turn red together?

• A. 20 seconds
• B. 30 seconds
• C. 45 seconds
• D. 40 seconds

Answer 1

The correct option is D 40 seconds

LCM of (2,5,8,10) = 40
so, all signals turn red together after interval of 40 seconds