Question

The three words “GOD IS LOVE" are flashed such that the words individually are switched on at regular intervals of 4, 7 and 9 seconds respectively and after they are switched on, the words are switched off after 2 sec, 4 sec and 5 sec respectively. If at time 't' all the words happened to switch off simultaneously, find the least time 't' which all three words will switch on simultaneously.
a) 252 sec
b) 126 sec
c) 94 sec
d) 38 sec

Answer 1

Answer:

462 sec

Step-by-step explanation:

GOD  switched on at regular intervals of 4 sec

And Switched off in 2 sec

=> GOD Switched off After 4 + 2 = 6 Sec

IS  switched on at regular intervals of 7 sec

And Switched off in 4 sec

=> IS Switched off After 7 + 4 = 11 Sec

LOVE  switched on at regular intervals of 9 sec

And Switched off in 5 sec

=> LOVE Switched off After 9 + 5 = 14 Sec

GOD , IS &  LOVE get switched off after  6 , 11 & 14 sec

To find all will switch off together

is find LCM of 6 , 11 & 14

=> LCM = 6 * 11 * 7 = 462 sec