Equation 1: x + y = 40 ; therefore y = 40 - x
Equation 2: 25x + 15y = 900
Find x first:
25x + 15 (40 - x) = 900
25x + 600 - 15x = 900
10x = 900 - 600
x = 300÷10
x = 30 hours Chris needs to spend for tutoring job
y = 40 - 30
y = 10 hours Chris needs to spend for referencing job
CL will always be the same as LD, the CD line is perpendicular to AB where the L is, so, the extreme points of CD will always be in the same distance of L.
Distribute on the left side
7.4a+22.2=3.2a+43.2
Subtract 3.2a from both sides
4.2a+22.2=43.2
Subtract 22.2 from both sides
4.2a=21
Divide both sides by 4.2
a=5
