There are seven SI base
units which are used in science, every unit has its own property or use:
Meter (length)
Kilogram (mass)
Second (time)
Kelvin (temperature)
Mole (amount of substance)
Ampere (electrical unit) and
Candela (luminous intensity)
<span>The SI unit of
measure for length (meter) would be most appropriate when we are measuring the
distance between two places or when we are taking measurement of something.</span>
Answer:
The number of boys in the school is;

Explanation:
Given that the ratio of boys to girls in a school is 5:4;

And there are 500 girls in the school.
The number of boys in the school will be;

Therefore, the number of boys in the school is;
Answer:
The percent of decrease can be calculated with this formula:
(Original value - New Value)/(Original Value)
In this case, the original value is 117 and the new value is 91.
So the percent of decrease is 26/117, or about 22%.
Hope this helps!