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Peacemaker

P5 Mathematics

Question post on Wed, 20/09/2017 10:26pm

Hi can help me with this question. Thks

Answer

alfretztay · Answer 1 · Post on Wed, 20/09/2017 10:55pm

The sum of 6 numbers is 624. A 7th number is added and the average of the 7 numbers increases by 3. The an 8th number is added and the average of the 8 numbers increases by 2. Find the 8th number.

624/6 = 104

Method 1 :
(104 + 3 + 2) x 8 – (104 + 3) x 7 = 123

Method 2 :
(104 + 3) x 7 = 749 (sum of the 7 numbers)
749/7 = 107
(107 + 2) x 8 = 872 (sum of the 8 numbers)
872 – 749 = 123

Ans : 123.

Peacemaker · Answer 2 · Post on Thu, 21/09/2017 6:38pm

Peacemaker Post on Thu, 21/09/2017 6:38pm

Thks!

alfretztay · Answer 3 · Post on Thu, 21/09/2017 8:26pm

alfretztay Post on Thu, 21/09/2017 8:26pm

U r welcome!