If one salesman sold 40 cards, which was 5% of the total cards sold for Mother's Day, then we can use this information to find the total number of cards sold.
To find the total number of cards sold, we can set up the following proportion:
(the number of cards sold by one salesman) / (the percentage of total cards sold by one salesman) = (total number of cards sold) / (100%)
So,
40 cards / 5% = x / 100%
To solve for x, we can cross-multiply and divide:
x = (40 cards * 100%) / 5%
x = 40 * 20
x = 800
Therefore, a total of 800 cards were sold for Mother's Day.