Q17 of 79 Page 25

The mean weight per student in a group of 7 students is 55 kg. The individual weights of 6 of them (in kg) are 52, 54, 55, 53, 56 and 54. Find the weight of the seventh student.

The mean weight per student in a group of 7 students = 55 kg

Weight of 6 students (in kg) = 52, 54, 55, 53, 56 and 54


Let weight of 7th student = x kg


Therefore, Mean =


55 =


385 = 324 + x


x = 385 – 324


x = 61 kg


Therefore, weight of 7th student = 61 kg


More from this chapter

All 79 →
15

The traffic police recorded the speed (in km/h) of 10 motorists as 47, 53, 49, 60, 39, 42, 55, 57, 52, 48. Later on an error in recording instrument was found. Find the correct overage speed of the motorists if the instrument recorded 5 km/hr. less in each case.

 16

The mean of five numbers is 27. If one number is excluded, their mean is 25. Find the excluded number.

 18

The mean weight of 8 numbers is 15. If each number is multiplied by 2, what will be the new mean?

 19

The mean of 5 numbers is 18. If one number is excluded, their mean is 16. Find the excluded number.