If there were two electricians, they'd need to install 48 fixtures per person.. if it takes 20 minutes for each fixture, it would take a total of 960 minutes, which converts to 16 hours. If a work day was only 8 hours, it would take two electricians TWO work days to install 96 light fixtures, or 24 light fixtures for four floors.
<span>40% = 40/100 = 2/5. Always put the ten's place numbers over 100, and look at it as if it were like quarters or any type of other money!</span>
Package A: 5kg, Package B: 10kg
Use a system of equations to find the weight of each package. Set up two equations with the knowledge you know about the combined weight of the packages, using 'a' as the variable for Package A and 'b' as the variable for Package B.
5a + 6b = 85kg and 10a + 4b = 90kg
Take the second equation and solve for a, which you will use to substitute into first equation. Subtract 4b from both sides and divide everything by 10.
10a = 90kg - 4b
a = 9kg - 2/5b
Plug a = 9kg - 2/5b into the equation 5a + 6b = 85kg.
5(9kg - 2/5b) + 6b = 85kg
45kg - 2b + 6b = 85kg
45kg + 4b = 85kg
4b = 40kg
b = 10kg
Put 10kg in for b for one of the equations and solve for a.
10a + 4(10kg) = 90kg
10a + 40kg = 90kg
10a = 50kg
a = 5kg
The weight of Package A is 5kg and the weight of package B is 10kg.
