If we let Q be the number of quarters and N be number of nickels, this is the formula we would use:
[1] 25Q + 5N = 635 (using cents instead of dollars)
We also know something about Q and N.
[2] Q + N = 51
So multiply both sides of the second equation by 5. The reason we do this is because we're going to need to cancel out one of the variables (either Q or N) to solve for the other one. If we multiply times 5, we'll have 5N in both equations.
5Q + 5N = 255
Now we have two equations, and the second one can be subtracted from the first.
25Q + 5N = 635
-(5Q + 5N) = -255
---------------------
20Q = 380
so
Q = 19
There are 19 quarters.
And since there are 51 coins in all, 51-19 = 32 nickels.
63 i believe correct me if i’m wrong somebody. Im possibly WAY off
Answer:
Step-by-step explanation:
Let's say the Physics book costs $x
The Chemistry book will cost $x - $6
Two such Chemistry books will cost;
2($x - $6) = $(2x - 12)
Three such Physics books cost $3x
$(2x - 12) + $3x = $123
$5x - $12 = $123
$5x = $111
x = $22
So the Physics book costs; $22
and the Chemistry book costs $22 - 6 = $16
The most likely number of cats = 21/37 x 8 = 4.54 ≈ 5 cats
The most likely number of dogs = 16/37 x 8 = 3.46 ≈ 3 dogs
The probability of that arrangement happening = 1/8^2 = 1/64 = 0.00156
