Question

The average of 4 numbers is 7. If the sum of first three numbers is 20, find the forth number

Answer 1

Answer:

Step-by-step explanation:

Let, 4th number be x. Then, 20+x/4=7. => 20+x=28. => x= 28-20. => x= 8.

Answer 2

Answer :

8

Step-by-step explanation :

Let the fourth number be x.

And, sum of all numbers = 20.

According to the question ;

Average of 4 numbers = 7

⇒ $\sf \frac{Sum \: of \: all \: numbers}{Total \: no \: of \: numbers}$ = 7

⇒ $\sf \frac{20 + x }{4}$ = 7

⇒ 20 + x = 4 × 7

⇒ 20 + x = 28

⇒ x = 28 - 20

⇒ x = 8

Hence, the fourth number is 8.