Answer: The answer is D
Step-by-step explanation: 12x means 12 times x, which means her age is 12 times her brother's age.
Answer:
10 ml of a 72% solution, 20 ml of a 54% solution
Step-by-step explanation:
x ml - amount of a 72% solution
y ml - amount of a 54% solution
(1)
(1) 2160-72y+54y=1800
y=20
x=30-y=30-20=10
Answer:
Step-by-step explanation:
In order for lines to be parallel they have to have the same slope. The first 2 equations there are solved for 5y, so let's do that to the last one--solve it for 5y--and put them all in the same order (the order that the first one is in; they will all look identical then). Equation #2 in the same order as in #1: 5y = 3x - 4. Equation #3 then becomes 5y = 3x - 1. Equations #2 and 3 have the same slope.
