Answer:
There are 24 nickels
Step-by-step explanation:
Let x represent the number of nickels
Let y represent the number of quarters
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Value Value
Type Number of of
of of each all
Coin Coin Coin Coin
—————————————————————
Nickels | x | $0.05 | $0.05x
Quarters | y | $0.25 | $0.25y
—————————————————————
Totals 28 ——— $2.20
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The first equation comes from the “Number of coins” column.
(Number of nickels) + (Number of quarters) = (total number of coins)
Equation: x + y = 28
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The second equation comes from the “value of all coins” column.
(Value of all nickels) + (Value of all quarters) = (Total value of all coins)
0.05x + 0.25y = 2.20
Remove the decimals by multiplying each term by 100:
5x + 25y = 220
—————————————————————
So we have the system of equations:
{x + y = 28
{5x + 25y = 202
Solve by substitution. Solve the first equation for y:
x + y = 28
y = 28 - x
Substitute (28 - x) for y in 5x + 25y = 220
5x + 25 (28 - x) = 220
5x + 700 - 25x = 220
-20x + 700 = 220
-20x = -480
x = 24
The number of nickels is 24.
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Substitute in y = 28 - x
y = 28 - (24)
y = 4
The number of quarters is 4.
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Checking:
24 nickels is $1.20 and 4 quarters is $1.00
That’s 28 coins.
Indeed $1.20 + $1.00 = $2.20
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5 and 12 are factors of 60
Answer:
12
Explanation:
3 pizza sizes multiplied by 4 appetizers = 12 possible outcomes.
hope it helps
Answer:
30 hens, 20 cows.
Step-by-step explanation:
Step one:
let the number of cows be x
and the number of hens be y
Each cow has 2 eyes, each hen has 2 eyes also.
the total number of eyes is
2x+2y
Each cow has 4 legs, each hen has 2 legs.
the total number of legs is
4x + 2y
Step two:
the number of legs exceeds the number of eyes by 40:
4x+2y - (2x+2y) = 40
open bracket
4x+2y-2x-2y=40
4x-2x=40
2x=40
Divide both sides by 2
x=40/2
x=20
Step three:
we know also that x = 2/3*y, so y = 3/2*x = 3/2 * 20 = 30
30 hens, 20 cows.
Check:
60 + 40 eyes = 100, 60 + 80 legs = 140legs.
Since the distance is 3.667km and the time is 1/3 of an hour (20 minutes) we take the distance and divide it with time 3.667/20 thus the answer is
0.183 km/hr