Question

37. The mean of the observations x,2x+1, 2x+5 and 2x+9 is 30. What is the mean of first three
observations?​

Answer 1

Answer:

Mean=x+2x+1+2x+5+2x+9/4

30=7x +15

30-15=7×

15/7 =x

x=2.1

Answer 2

▂ ▄ ▅ ▆ ▇ █ SOLUTION █ ▇ ▆ ▅ ▄ ▂

• GIVEN
• The mean of observation
• X,2x+1,2x+5,2x+9

$⇒mean = \frac{sum \: of \: observation}{number \: of \: observation} \\ \\ ⇒30 = \frac{x + 2x + 1 + 2x + 5 + 2x + 9}{4} \\ \\ ⇒30 = \frac{7x + 15}{4} \\ \\ ⇒7x + 15 = 120 \\ \\ ⇒7x = 120 - 15 \\ \\ ⇒7x = 105 \\ \\ ⇒x = 15$

☆The mean of first 3 observation are

$↪x = 15 \\ \\ ↪2x + 1 \\ \\ ↪2 \times 15 + 1 = 31 \\ \\ ↪2x + 5 \\ \\ ↪2 \times 15 + 5 = 35$