Think more, mathematicians
In a list of five numbers, the first number is 2 and the last number is 12. The product of
the first three numbers is 30, the product of the three in the middle is 90 and the product of the last three numbers is 360. Which number is in the centre of the list?
The answer is 5.
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1 solution
let the numbers in the middle be x,y and z. so, 2xy=30 --- (1), xyz=90 ---(2), 12yz=360 ---(3) now, from (2) dividing by (1) we get z=6. substituting the value of z in (3), we get y=5.