00:01
A jar of coins contains nickels, dims, and quarters.
00:17
So we know nickels is 5 cents, okay? we know deems is 10 cents.
00:27
We know quarters is 0 .25 cents, okay? so total number of coins is 12.
00:38
Number of coins is 12.
00:44
And the total value is 2 .35.
00:47
How many of each coin are there? okay, so we assume that we have assumed there are x equals, y deems, and z quarters.
01:42
Okay, so we can set up an equation set, which is 0 .05 times x, 0 .1 times y plus 0 .25 times z equals $2 .35 and we have x plus y plus z together we have 12 coins okay so since we have three variables and we only have two equations so it might be a little bit difficult to solve for x y and z okay so what we need to do is okay we need to try okay try this out so let's see for equation two we we solve for z equals 12 minus x minus y okay so we can name this three and we substitute this back to equation 1 okay so this is what i have times 12 minus x minus y okay so this equals 2 .35 so 0 .05 times x plus 0 .05 times 12 we have this is 0 .3 okay sorry not just 3 okay minus 0 .25 times x minus 0 .25 times y equals 2 .35 okay we can we cancel out x we have minus 0 .2 times x and minus 0 .15 times y, okay, we cancel out y, and we have equals minus 0 .65, okay? so let's turn everything into a positive.
03:59
So i have 0 .2 times x plus 0 .15 times y equals 0 .65.
04:05
Okay, we need to try x and y, since we don't have a third equation to help have us to solve for x and y.
04:12
Okay, we need to try.
04:13
So try, let's see, if x equals if x equals 2, okay, y equals y equals 3, this works? okay, so to be clear, i need to give you a reminder, okay? reminder here.
04:45
The reminder is x and y are both integers, okay? since this x and y represent the number of coins, okay? okay, so maybe let's see if x equals 1 and 1, y equals 3, this works, okay? so 0 .2 times 1 plus 3 times 0 .15, we have this is 0 .2 plus 0 .45 equals 0 .65, okay...