Question

The mean of a, b, c, d and e is 28. If the mean of a, c and e is 24, what is the mean of b and d?
A. 31
B. 32
C. 33
D. 34

Answer 1

Answer:

34

Step-by-step explanation:

Mean of a b c d e

(a+b+c+d+e)/5=28

a+b+c+d+e=140 ....(1)

mean of a c e

(a+c+e)/3=24

a+c+e=72

substitute in equation (1)

b+d+72=140

b+d=68

(b+d)/2=34

Mean of b&d is 34

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Answer 2

Answer:

Formula for calculating Mean:

• Mean = Sum of all observations ÷ Total Number of Observations

According to the question, Mean of observations a, b, c, d and e is 28.

→ Sum of all observations = a + b + c + d + e = x

→ Total number of observations = 5

→ Mean = 28

Substituting in the formula, we get:

→ 28 = x / 5

→ x = 28 × 5 = 140  [ Sum of all observations ]

Now it is also given that:

→ Mean = 24

→ Observations = a, c and e

→ Total number of observations = 3

→ Sum of observations = a + c + e = y

Substituting in the formula, we get:

→ 24 = y / 3

→ y = 24 × 3 = 72  [ Sum of a, c and e ]

Now we know that,

→ a + b + c + d + e = x

→ ( a + c + e ) + b + d = x

→ y + ( b + d ) = x

→ b + d = x - y

→ b + d = 140 - 72

→ b + d = 68

Therefore Mean of b and d is given as:

→ Mean = ( b + d ) / 2

→ Mean = 68 / 2

→ Mean = 34

Therefore mean of the observations 'b' and 'd' is 34.