Answer:
49 cm²
Step-by-step explanation:
Formula for area:
a = l (length) x w (width)
if its 7 cm on each side, then the length and width will be 7
7*7 = 49 cm²
Answer: Division
Parentheses first according to the order of operations, and the next thing you do is divide inside the parentheses.
Answer:
John should use:
4 grams of the 30% solution and 16 grams of the 60% solution
Step-by-step explanation:
Let the number of grams of the 30% solution = x
Let the number of grams of the 60% solution = y
John needs 20 grams of 54% acid solution for his science project.
Hence,
x + y = 20 grams..... Equation 1
x = 20 - y
His school's science lab has bottles of 30% solution and bottles of 60% solution.
30% × x + 60% × y = 54% × 20
0.3x + 0.6y = 10.8......Equation 2
We substitute 20 - y for x in Equation 2
0.3(20 - y) + 0.6y = 10.8
6 - 0.3y + 0.6y = 10.8
- 0.3y + 0.6y = 10.8 - 6
0.3y = 4.8
y = 4.8/3
y = 16 grams
x = 20 - y
x = 20 - 16
x = 4 grams
Therefore, John should use:
4 grams of the 30% solution and 16 grams of the 60% solution
Use pemdas, multiply 3 • 4 and you’ll get 12. Add 6 and the answer is 18
Answer:
1.25 litros.
Step-by-step explanation:
Dado que Demetrio compró dos litros de leche, y luego utilizó 3 cuartos de litro en un postre, para determinar cuánta leche le quedó se debe realizar el siguiente cálculo matemático:
2 - 3/4 = X
2 - 0.75 = X
1.25 = X
Así, tras utilizar 3 cuartos de litro de leche en un postre, a Demetrio le quedaron 1.25 litros de leche.
