the original price is "x", or 100%.
but we know that if we reduce "x" by 20%, namely 100% - 20% = 80%, the 80% of "x" is really £50, what is "x" or the 100% anyway?

Answer:
The total weight of the metal bar in pounds is 25 pounds
Step-by-step explanation:
Now, we have a metal bar which has a content of 60% zinc corresponding to 15 pounds.
Mathematically, let’s say the total weight of the metal composite is x pounds. It is 60% of this that is 15 pounds which is the content of the zinc
Mathematically;
60/100 * x = 15
60x = 15 * 100
60x = 1500
x = 1500/60
x = 25 pounds
The rule of scientifinc notation is that we can use number between 0 and 10, so here we can use 2.8. Lets do this
280 000 000 = 2.8 * 100 * 1 000 000
Now we can just multiply 2.8 by 10 to the power of number of 0 reapeted
So

- its the result
Answer:
z= 13
x= 36
y= 18
Step-by-step explanation:
Solving for z.
We know that 108 degrees and (8z+4) are alternate exterior angles, so they are equal to each other.
We can set both of those angles equal to each other, and solve for our missing side, z.
108= 8z+4
104=8z
z= 13
Solving for x.
We know that 108 degrees and (3x) are alternate interior angles, so they would equal each other.
We can set both of these angles equal to each other, and solve for our missing side, x.
3x=108
x= 36
Solve for y.
We know that (4y) and (3x) are same side interior angles, so they would make 180 degrees. We know that (3x) would equal 108.
4y+108=180
4y= 72
y= 18
Unsure of what you're asking.
If you have an algebraic expression in front of you and see a number there, you could label it as "known" or "a known quantity." Another word that comes to mind is "constant."