Step-by-step explanation:
If x is the mass of 30% copper alloy, and y is the mass of 65% copper alloy, then:
x + y = 80
0.30x + 0.65y = 0.51(80)
Solving the system of equations using substitution:
0.30x + 0.65(80 − x) = 0.51(80)
0.30x + 52 − 0.65x = 40.8
11.2 = 0.35x
x = 32
y = 80 − x
y = 48
The metalworker needs 32 kg of 30% copper alloy and 48 kg of 65% copper alloy.
If the are equal then they can be similar, otherwise they are not.
The statement "y varies directly as x," means that when x increases, y increases by the same factor. In other words, y and x always have the same ratio: y/x =K
it can be written as ---> y=kx
then put in the values to get a common ratio
k= y/x
k1= 11/7
k2= 13/8
therefore, there's no common ratio in the given table
Answer:
x = 28
Step-by-step explanation:
If a line parallel to one side of a triangle intersects the other two sides of the triangle, then the line divides these two sides proportionally.
Then x/(x +10) = 42/(42 +15)
x(57) = 42(x + 10)
57x = 42x + 420
15x = 420
x = 28