Tuition Center Singapore Maths Tuition – Prime Numbers and LCM

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Tuition Center Singapore Maths Tuition – Prime Numbers and LCM

Question

(a)        Express each of the numbers 14, 21 and 49 as a product of its prime factors.

(b)       Three train services operate from the same station. The first service leaves at    14-minute intervals, the second at 21-minute intervals and the third at 49-minute intervals. All three services leave the station together at 19 30 hours on Thursday. When will the three train services next leave the station together?

Solution

a)

14 = 2 x 7

21 = 3 x 7

49 = 7 x 7

b)

LCM of 14, 21, 49 = 2 x 3 x 7 x  7 = 294

294 = 4 hours 54 minutes

The three train services next leave the station together at 0024 hours on Friday.

If you need help in Secondary 1 to Secondary 4 Mathematics, please contact Angie @96790479 or Mr Ong @ 98639633