In a certain year, the average e-mail user sent or received 143 e-mails each day. The number of e-mails received was 3 more than thrice the number sent. How many were sent and how many were received each day?

Each day, 71 mails were sent and 216 mails were received.

Step-by-step explanation:

Step 1: Given average mails sent and received is 143. Let the number of sent mails be x. So the number of received mails = 3x + 3. Form an equation out of this, to find x.

⇒ Average = (x + 3x + 3) / 2

⇒ 143 = 4x + 3/2

⇒ 286 = 4x + 3

⇒ 4x = 283

⇒ x = 70.75 ≈ 71

and 3x + 3 = 3 * 71 + 3 = 213 + 3 = 216

35 emails sent 108 emails received in each day.

Step-by-step explanation:

Let the number sent = x

Let the number received = y = 3x + 3

According to given condition

x + 3x + 3 = 143

4x + 3 = 143

4x = 143 - 3

4x = 140

x = 140/4

x = 35

y = 3 (35) + 3

y = 108

35 emails sent 108 emails received in each day.