0<x<10, Is 2z > x+10? Or rephrased Is x < 2z - 10? Can z get any value that 2z-10 isn't positive value?
st(1) z is closer to 10 case. If z=5 then 2z-10 isn't positive. Can this be possible? No, because if z=5, then x must be less than 0. Answer is Yes, Sufficient.
st(2) z=5x case. Plug into inequality x<2z-10 and rewrite as x<10x-10, 9x>10, x>10/9. The latter implies that x could be anything starting from 10/9 and to the positive infinity, which is not acceptable as question specifies x<10. Not Sufficient.
a
dreamv wrote:If x is a positive number less than 10, is z greater than the average(arithmetic mean) of x and 10?
1)On the number line, z is closer to 10 than it is to x
2)z=5x
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