The value of the coin times the number of coins all added up equals the total value of the piggy bank
so
0.05n + 0.10d = 5.60
then they have given us "number of nickels is 8 less than 3 times the dimes"
this translates to
n = 3d - 8
we plug this into our first equation and we get
0.05(3d - 8) + 0.10d = 5.60
now we solve for d
first we can distribute the 0.05
0.15d - 0.40 + 0.10d = 5.60
then we can add the 0.15d and 0.10d together
and get
0.25d - 0.40 = 5.60
then we can add 0.40 to both sides
0.25d = 6.00
then divide both sides by 0.25
d = 6.00 / 0.25 = 24
so we have 24 dimes
then to find nickels, we plug in 24 for d into
n = 3d - 8
and get
n = 3(24) - 8
n = 72 - 8
n = 64
therefore we have
64 nickels
and
24 dimes
3x - y + z = 5 . . . (1)
x + 3y + 3z = -6 . . . (2)
x + 4y - 2z = 12 . . . (3)
From (2), x = -6 - 3y - 3z . . . (4)
Substituting for x in (1) and (3) gives
3(-6 - 3y - 3z) - y + z = 5 => -18 - 9y - 9z - y + z = 5 => -10y - 8z = 23 . . (5)
-6 - 3y - 3z + 4y - 2z = 12 => y - 5z = 18 . . . (6)
(6) x 10 => 10y - 50z = 180 . . . (7)
(5) + (7) => -58z = 203
z = 203/-58 = -3.5
From (6), y - 5(-3.5) = 18 => y = 18 - 17.5 = 0.5
From (4), x = -6 - 3(0.5) - 3(-3.5) = -6 - 1.5 + 10.5 = 3
x = 3, y = 0.5, z = -3.5
Answer:
Step-by-step explanation:
789
Answer:
Step-by-step explanation: