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Secondary 1 | Maths
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= 2 x 27
= 2 x 3 x 3 x 3
= 2 x 3³
72
= 2 x 36
= 2 x 2 x 18
= 2 x 2 x 2 x 9
= 2 x 2 x 2 x 3 x 3
= 2³ x 3²
150
= 2 x 75
= 2 x 5 x 15
= 2 x 5 x 5 x 3
= 2 x 5² x 3
Minimum power of 5 we need = 2
Minimum power of 2 we need = 3
LCM = 3³ x 5² x 2³
= 27 x 25 x 8
= 27 x 200
= 5400
5400 seconds
= (5400 ÷ 60) min
= 90 min
90 min later, they will all flash together again.
90 min = 1h 30 min
So 0635 h + 0130 h
= 0765 h
= 0805 h
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