12u + 12(15) = 756
multiply 12 and 15
12u + 180 = 756
subtract 180 from both sides
12u = 576
divide 12 on both sides
u = 48
When you add it mentally you'd get 29
When you subtract it mentally you'd get 4.8
The answer would be 0.01 because 1 is one and 0.1 is one tenth.
Answer:
There needs to be 300 liters of Drink A and 270 liters of Drink B
Step-by-step explanation:
Let a = the amount of Drink A and b = the amount of Drink B
Multiplying a number by 0.2 is the same as calculating 20% of it and same goes with 15% and 0.15. This makes our equation for the amount of fruit juice:
0.2a + 0.15b = 100.5
We know what the difference between a and b will be 30 liters so:
a - b = 30
Now we have our system of equations
To cancel out a, we can multiply the first equation by -5 so we will now have:
-a - 0.75b = -502.5
a - b = 30
Adding these two equations together, we get:
-1.75b = -472.5
Both sides are negative, so we can take the negative signs away.
1.75b = 472.5
Now divide both sides by 1.75
b = 270
Plugging 270 into b, we have:
a - b = 30
a - 270 = 30
Add 270 to both sides
a = 300
There needs to be 300 liters of Drink A and 270 liters of Drink B
