This is simple algebra :)
First, we can write the question as an algebraic equation.
Given that Doug spent 40 more hours than Laura, we can represent Laura as (x) and Doug as (x+40).
"Doug and Laura spent a combined 250 hours." So we can write this as
(x) + (x+40) = 250
Now simplify:
2x + 40 = 250
Solve x by subtracting 40 from both sides of the equation:
2x = 210
Therefore:
x = 210/2
= 105
So Laura (x) spent 105 hours!
Equation 1 minus equation 2 to eliminate x: 3y+2z=3
equation 1 plus equation 3 to eliminate x: 5y+6z=5
now focus on these new system of equation, multiply 3y+2z=3 by 3:
9y+6z=9
subtract 5y+6z=5 from 9y+6z=9 to eliminate z: 4y=5, y=1
Plug y=1 into 3y+2z=3 to find z: z=0
Plug y=1, z=0 into any of the three equations to find x. I'll use equation 1:
-2x+2+0=0, x=1
so the solution is x=1, y=1, z=0
Answer:
I think it's all of them :)
Answer:
- 16.7° C
Step-by-step explanation:
Decreasing by - 1.5° C means subtracting this from - 15.2° C , that is
- 15.2° C - 1.5° C = - 16.7° C