If the mean of 4 numbers, 2,6,7 and a is 15 and also the mean of other

1.	If the mean of 4 numbers, 2,6,7 and a is 15 and also the mean of other 5 numbers, 6, 18 , 1, a, b is 50. What is the value of b?
Answer» MEAN = sum of observations / no. of observations 15 = (2 + 6 + 7 +a)/4 15 = (15 + a) / 4 15 x 4 = 15 + a 60 – 15 = a a = 45 Similarly, Mean = sum of observations / no. of observations 50 = (18 + 6 + 1 +a + b)/5 50 = (18 + 6 + 1 +45 + b)/5 50 = (70 + b)/5 250 = 70 + b b = 250 – 70 = 180 So, The value of b = 180

If the mean of 4 numbers, 2,6,7 and a is 15 and also the mean of other 5 numbers, 6, 18 , 1, a, b is 50. What is the value of b?

Answer»

MEAN = sum of observations / no. of observations

15 = (2 + 6 + 7 +a)/4

15 = (15 + a) / 4

15 x 4 = 15 + a

60 – 15 = a

a = 45

Similarly, Mean = sum of observations / no. of observations

50 = (18 + 6 + 1 +a + b)/5

50 = (18 + 6 + 1 +45 + b)/5

50 = (70 + b)/5

250 = 70 + b

b = 250 – 70 = 180

So, The value of b = 180