April has 30 days. One year, April had exactly four Saturdays. On which two days of the week could April 1 not have occurred that year?

Friday and Saturday

Step-by-step explanation:

No. of days in April = 30

No. of days in one week = 7

So, if we divide 30 by 7 we get 4 as a quotient and 2 as a remainder

Quotient 4 shows that every day of the week will occur at least 4 times. And the remainder 2 shows that any 2 days of the week will occur 5 times.

Now for month April to have exactly 4 Saturdays, last 2 days must not be : Friday Saturday or Saturday Sunday because in this case the Saturday will occur 5 times.

So, For April to have exactly 4 Saturdays, April 1 may not have occurred on Friday or Saturday because in both the cases the Saturday will occur 5 times.

Hence, the required days of the week are : Friday and Saturday