Question

Пони в течение трех дней рассылал четвероклассникам приглашения на участие в Турнире. Причем каждый новый день он отправлял столько приглашений, сколько за все предыдущие дни вместе. Сколько приглашений отправил Пони в первый день, если за три дня он отправил 112 приглашений?

Answer 1

В первый день он отправил x приглашений. Во второй день столько же, сколько в первый, то есть тоже x. В третий столько же, сколь в первый и второй в сумме, то есть (x+x) = 2x. Всего за 3 дня 112 приглашений, то есть
x+x+2x = 112
4x = 112
x=112:4
x = 28 приглашений.

Answer 2

Problem Analysis

Pony sent invitations to fourth graders for three days. Each day, he sent invitations equal to the total number of invitations he had sent in all the previous days combined. We need to determine how many invitations Pony sent on the first day, given that he sent a total of 112 invitations over the three days.

Solution

Let's solve this problem step by step.

1. On the first day, Pony sent a certain number of invitations. 2. On the second day, Pony sent the same number of invitations as the total number of invitations he had sent on the first day. 3. On the third day, Pony sent the same number of invitations as the total number of invitations he had sent on the first and second days combined.

To find the number of invitations Pony sent on the first day, we can use a simple equation:

Number of invitations on the first day + Number of invitations on the second day + Number of invitations on the third day = Total number of invitations

Let's represent the number of invitations on the first day as 'x'. Then:

x + x + (x + x) = 112

Simplifying the equation:

4x = 112

Dividing both sides of the equation by 4:

x = 112 / 4 = 28

Therefore, Pony sent 28 invitations on the first day.

Answer

Pony sent 28 invitations on the first day.

Verification

To verify this answer, let's calculate the total number of invitations Pony sent over the three days:

Number of invitations on the first day: 28 Number of invitations on the second day: 28 + 28 = 56 Number of invitations on the third day: 28 + 28 + 56 = 112

The total number of invitations sent over the three days is indeed 112, confirming that Pony sent 28 invitations on the first day.