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cupoosta [38]
3 years ago
5

The average of 3 numbers is 7. two of the numbers are 8 and 9. what is the third?

Mathematics
2 answers:
pishuonlain [190]3 years ago
8 0
Make an equation. x will be the third number.

To find the average, you add up the numbers then divide the sum by the number of numbers you added up.

(8 + 9 + x) ÷ 3 = 7
Now solve. Add up like terms (8 + 9).

(17 + x) ÷ 3 = 7
Multiply both sides by 3.

17 + x = 21
Subtract both sides by 17.

x = 4

The third number is 4.
Ratling [72]3 years ago
7 0
(8+9+x)/3=7
(17+x)=21
x=4
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