Question

Q.2. The average of 4 terms is 20 and the 1st term is 1/3 of the remaining terms. What will be the first number?

A. 30

B. 20

C. 60

D. 80

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Answer 1

Answer:

d.80

Step-by-step explanation:

You meant to write “the 1st term is 1/3/ of each of the remaining terms”, correct? If that is the case, and the average of the four terms is twenty then the sum of the four terms is eighty, then let x represent the first term and 3x represent each of the other terms. Then x + 3(3x) = 80, which implies that 10x = 80 and x = 8. the first term is eight.

To check, the other terms are 3(8) or 24, and 8 + 24 + 24 + 24 = 80.

Hope it helps.

Answer 2

Answer:

$\bigstar{\bold{Option\:B:20}}$

Step-by-step explanation:

$\Large{\underline{\underline{\bf{Given:}}}}$

• Average of first 4 terms is 20
• First term = 1/3 of remaining terms

$\Large{\underline{\underline{\bf{To\:Find:}}}}$

• First number

$\Large{\underline{\underline{\bf{Solution:}}}}$

→ Let the first term be a

→ Let the second term be b

→ Let the third term be c

→ Let the fourth term be d

→ By given

  (a + b+ c + d)/4 = 20

   a + b + c + d = 20 × 4

   a + b + c + d = 80

   a = 80 - (b + c + d )----(1)

→ Also by given,

  a = (b+ c + d)/3

  3a = b + c + d---(2)

→ Substitute 2 in 1

 a = 80 - 3a

 3a + a = 80

  4a = 80

    a = 80/4

    a = 20

→ Hence the first term is 20

$\boxed{\bold{First\:term=20}}$

→Hence option B is correct