A100 meter dash was held with 20 contestants. the best time was 10.7 seconds, and the worst time was 15.3 seconds. only the fastest 10 contestants advance to the final race. which measure of central tendency should be used to calculate the cutoff time for the final race? a. median b. mode c. mean d. range

median

Explanation:

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explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.