A grocer gets food from three suppliers. They deliver every 5 days, 6 days and 7 days, respectively. All three came today. When will they all deliver on the same day again?

5*6*7 least common multiple

210

To find out when all three suppliers will deliver on the same day again, we need to find the least common multiple (LCM) of the three delivery intervals.

The delivery intervals are 5, 6, and 7 days.

To find the LCM, we can list the multiples of each number until we find a common multiple:
- The multiples of 5 are: 5, 10, 15, 20, 25, ...
- The multiples of 6 are: 6, 12, 18, 24, 30, ...
- The multiples of 7 are: 7, 14, 21, 28, 35, ...

The first number that appears in all three lists is 30.

Therefore, the grocer will receive deliveries from all three suppliers on the same day again in 30 days.