Question 43

Jambmaths question: 

The mean of seven numbers is 96. If an eight number is added, the mean becomes 112. Find the eighth number.

Option A: 

126

Option B: 

180

Option C: 

216 

Option D: 

224

Jamb Maths Solution: 

Mean of seven numbers =${{\overline{x}}_{7}}=96$

Total summation of the 7 numbers$=96\times 7=672$

Mean of the eight numbers =  ${{\overline{x}}_{8}}=112$

Total summation of the 7 numbers$=112\times 8=896$

The 8th number is 892 – 672 =224

 

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