Jenson jogged at the swimming pool once every 3 days. Ivan jogged at the same swimming pool once every 7 days. They met on 5 March 2018. There are 31 days in March and 30 days in April.
- On which date they next met each other at the swimming pool? Give your answer at the following format. (Eg 1 Jan 2000)
- How many times did they meet at the swimming pool at March and April 2018?
(a)
Multiples of 3: 3, 6, 9, 12, 15, 18, 21
Multiples of 7: 7, 14, 21
LCM of 3 and 7: 21
Jenson and Ivan met every 21 days.
21 days after 5 March 2018 = 26 Mar 2018
The day that they next met at the swimming pool = 26 Mar 2018
(b)
Since Jenson and Ivan first met on 5 March 2018, they did not meet for the first 4 days of March 2018.
Total number of days from 5 March 2018 to 30 April 2018
= 31 + 30 - 4
= 57
Number of sets of 21 days from 5 March to 30 April 2018
= 57 ÷ 21
= 2 r 15
On the first day of each of the 2 sets of 21 days, they would meet at the swimming pool.
Since there is a remainder of 15, this means that on the first day of the remaining 15 days, they would meet at the swimming pool again.
Number of times that they met at the swimming pool in March 2018 and April 2018
= 2 + 1
= 3
Answer(s): (a) 26 Mar 2018; (b) 3
