Question

Купили 3 больших и7 маленьких конвертов.На 3 конверта наклеили марки. Мог ли остаться хоть один большой конверт без марки? На коки конверты могли наклеить марки? Рассмотри все варианты

Answer 1

Ты можешь наклеить на 2 больших и на одну маленькую.У тебя останеться один большой конверт и 6 маленьких.

Answer 2

Can a large envelope be left without a stamp?

If we have 3 large envelopes and 7 small envelopes, and we put stamps on 3 of the envelopes, we need to determine if it is possible for at least one large envelope to be left without a stamp.

To solve this problem, we can consider the different scenarios and calculate the possibilities.

Scenario 1: All 3 large envelopes have stamps

In this scenario, all 3 large envelopes have stamps, and therefore, no large envelope is left without a stamp.

Scenario 2: 2 large envelopes have stamps

In this scenario, 2 out of the 3 large envelopes have stamps. We need to calculate the number of ways this can happen.

To calculate the number of ways to choose 2 large envelopes out of 3, we can use the combination formula: C(n, r) = n! / (r!(n-r)!), where n is the total number of items and r is the number of items to be chosen.

In this case, n = 3 (the total number of large envelopes) and r = 2 (the number of large envelopes with stamps). Plugging these values into the formula, we get:

C(3, 2) = 3! / (2!(3-2)!) = 3

So, there are 3 ways to choose 2 large envelopes out of 3.

Scenario 3: 1 large envelope has a stamp

In this scenario, only 1 out of the 3 large envelopes has a stamp. We need to calculate the number of ways this can happen.

Using the combination formula again, we can calculate:

C(3, 1) = 3! / (1!(3-1)!) = 3

So, there are 3 ways to choose 1 large envelope out of 3.

Scenario 4: No large envelopes have stamps

In this scenario, none of the 3 large envelopes have stamps. This is the case we are interested in.

To calculate the number of ways this can happen, we subtract the total number of ways from the previous scenarios from the total number of possibilities.

Total number of possibilities = C(10, 3) = 10! / (3!(10-3)!) = 120

Total number of ways from previous scenarios = 3 + 3 = 6

Number of ways no large envelopes have stamps = Total number of possibilities - Total number of ways from previous scenarios = 120 - 6 = 114

So, there are 114 ways in which at least one large envelope can be left without a stamp.

How many envelopes can have stamps?

Now let's consider the different possibilities for the number of envelopes that can have stamps.

1. All 3 large envelopes can have stamps. 2. 2 large envelopes can have stamps, and 1 large envelope can be left without a stamp. 3. 1 large envelope can have a stamp, and 2 large envelopes can be left without stamps. 4. No large envelopes have stamps.

So, the possible combinations for the number of envelopes that can have stamps are: 3, 2, 1, or 0.

Conclusion

In summary, if we have 3 large envelopes and 7 small envelopes, and we put stamps on 3 of the envelopes, it is possible for at least one large envelope to be left without a stamp. There are 114 ways in which this can happen. The possible combinations for the number of envelopes that can have stamps are 3, 2, 1, or 0.