Answer:
90 and 30 liters
Step-by-step explanation:
1) if solution of 20% is 'x' and of 60% is 'y' liters, then
2) the pure chlorine is: for solution of 20% - 0.2x, for solution of 60% - 0.6y and
3) the mix of the two solutions is 120=x+y.
4) using these items it is possible to make up the system of two equations:

5) finally, x=90 liters of 20%; y=30 liters of 60% solution.
A square pyramid has 4 triangles and the square base.
Calculate the area of one triangle, multiply that by 4 then add the area of the base.
Area of triangle = 1/2 x base x height = 1/2 x 5 x 12 = 30 square yards.
30 x 4 = 120 square yards
Area of base = 5 x 5 = 25 square yards
Total = 120 + 25 = 145 square yards.
Answer: 7(3m - 7n)
<u>Step-by-step explanation:</u>
Factor each term then see what value(s) they have in common:
21m - 49n
∧ ∧
3 · 7 · m 7 · 7 · n
Both terms have a 7 in common. What is left over after removing the 7?
21m: 7(3m)
49n: 7(7n)
GCF: 7 Leftovers: 3m <em>and</em> 7n
Factored form of expression is: 7(3m - 7n)
Answer:
120 I think.
Step-by-step explanation:
Because 10*12=120