25q + 10d = 425
q + d = 20
First thing's first, picture 4 quarters. Do you know how much these 4 quarters are worth? Obviously, you'd answer one dollar, but take the time to think about how exactly you came up with this answer.
"Well, it's simple," you might think, "Multiply 0.25 by 4."
Similar to this train of thought, the first equation is formulated by doing exactly that. 'q' represents an unknown number of quarters, and 'd' an unknown number of dimes. We use 25q and 10d, because, well, we're multiplying their value by the number of coins. They're equivalent to 425 because the 20 unknown coins make $4.25 (I converted it to cents to get rid of the pesky decimals, but if you want to keep it as dollars that works too).
Because the equation states that there are 20 coins in total, we know that we can make the equation 'q + d = 20' since there are 20 quarters and dimes in total.
Let me know if you need any further explanation :)
-T.B.
There are a number of possible combinations for this open-ended question, so here's an example question and answer, in which the two are non-related:
James' car is going at 45 miles per hour, and that is 42% of his maximum speed. How much slower does James have to go to be 27% of his maximum speed?
Amy's car used to be able to go at 45 miles per hour as 42% of her maximum speed, but due to the new upgrade, 45 miles per hour is now only 27% of her maximum speed.
Answer:
The constant is 2.7. This number never changes.
Answer:
A.+4
Step-by-step explanation:
Graph pass (1 , 0) and (4 , 0)
y = (x - 1) (x - 4) = x² - 5x + 4
c = 4
Answer:
Below in bold.
Step-by-step explanation:
No repetition.
There are a total of 7 numbers.
For the number to be even it must end in 0, 2 or 8.
The other 3 numbers will be the number of permutations of 3 from the 6 other numbers.
Number of 4 digit numbers ending in 0
= 6P3 = 6! / 6-3!
= 120.
Now the number could also end in 2 or 8,
so there are 3*120 = 360 4-digit even numbers (no repetition).
With repetition.
There are 3 * 7^3 = 1029 with repetition.
